**About the Editors**

**Matthew Wickman** is Professor of English and Founding Director of the BYU Humanities Center. He is the author of *The Ruins of Experience: Scotland's "Romantick" Highlands and the Birth of the Modern Witness* (U of Pennsylvania Press, 2007), *Literature After Euclid: The Geometric Imagination in the Long Scottish Enlightenment* (U of Pennsylvania Press, 2016), and numerous articles that span across various humanities disciplines. His current work explores the relationship between literature and spirituality, with particular emphasis on the multiple forms and expressions of experiences of ultimate value.

**Jacob Sherman** is Professor and Chair of the Philosophy and Religion Department at the California Institute of Integral Studies. He taught previously at King's College London and the University of Cambridge. In addition to numerous articles and essays in philosophy, theology, and religious studies, he is the author of *Partakers of the Divine: Contemplation and the Practice of Philosophy* (Fortress Press, 2014), and editor, with Jorge Ferrer, of *The Participatory Turn: Spirituality, Mysticism, Religious Studies* (SUNY Press, 2007). He is currently working on a new manuscript addressing the theological, philosophical, and ecological aspects of 'The Book of Nature'.


**6. Conclusion**

In this paper we have described numerical schemes and their implementation for the solution of scattering of a plane wave by two different cylindrical structures: a single-cornered structure and a second structure with two corners, each with three different boundary conditions imposed on their surfaces - soft, hard and an impedance boundary condition. We have numerically demonstrated that the field scattered by the rounded structure converges, in both the *L*2 and *L*∞ norm, to that scattered by the corresponding sharp cornered object as the radius of curvature in the vicinity of the corner tends to zero.

It is important to use an appropriate quadrature scheme - a graded mesh - in order to obtain numerical results efficiently, for both the scatterer with sharp corners and for the scatterer with rounded corners possessing small radii of curvature. We anticipate that improvements to the graded mesh employed for the two-cornered object will match the rate of convergence demonstrated for the single-cornered lemniscate.

Our results show that for the soft boundary condition, the *L*∞ norm difference between the near or far scattered field of the single-cornered scatterer and that of the rounded scatterer is less than 4% when the radius of curvature is restricted so that *kρ* ≤ 3*π*/50. This percentage reduces to 3% or 2% respectively, when the boundary condition is replaced by the Neumann boundary condition or the impedance boundary condition (with *λ* = 1 + *i*), respectively. More precise measures of the difference are given in Table 4. Similar results were obtained for the the two-cornered object, and are displayed in Table 8.

Our approach provides a relatively simple yet efficient and accurate method for computing near and far-fields scattered by sharp cornered objects of diameter *D* up to a few wavelengths in extent. Accuracy was of paramount importance in this study in assessing the effects of rounding a corner. Our calculations rigorously examined the regime 1 ≤ *ka* ≤ 10 corresponding to 0.318 ≤ *D*/*λ*0 ≤ 3.18, where *λ*0 is wavelength.

A more sophisticated approach to the scattering from soft cylindrical structures with sharp corners is given in [7]. It employs the so-called recursively compressed inverse preconditioning method, and as the authors note in their survey of the two dimensional scattering literature, it alone addresses the problem of accurate near-field evaluation in scatterers with corners.

In conclusion, this paper provides some precise quantification and assessment of the impact that the rounding of the corner of a sharp cornered object has on the scattering of acoustic waves. The method would seem to be extendible considerably beyond the wavelength range examined, constrained mainly by computer resources.


**Relevance of the Preparation of the Target for PLD on the Magnetic Properties of Films of Iron-Doped Indium Oxide**

#### **Hasan B. Albargi 1,2, Marzook S. Alshammari 3,\*, Kadi Y. Museery 3, Steve M. Heald 4, Feng-Xian Jiang 5, Ahmad M. A. Saeedi 1, A. Mark Fox 1 and Gillian A. Gehring 1,\***

Received: 2 May 2019; Accepted: 10 June 2019; Published: 13 June 2019

**Abstract:** This paper concerns the importance of the preparation of the targets that may be used for pulsed laser deposition of iron-doped indium oxide films. Targets with a fixed concentration of iron are fabricated from indium oxide and iron metal or one of the oxides of iron, FeO, Fe3O4 and Fe2O3. Films from each target were ablated onto sapphire substrates at the same temperature under different oxygen pressures such that the thickness of the films was kept approximately constant. The films were studied using X-ray diffraction, X-ray absorption (both XANES and EXAFS), optical absorption and magnetic circular dichroism. The magnetic properties were measured with a SQUID magnetometer. At the lowest oxygen pressure, there was evidence that some of the iron ions in the films were in the state Fe2+, rather than Fe3+, and there was also a little metallic iron; these properties were accompanied by a substantial magnetisation. As the amount of the oxygen was increased, the number of defect phases and the saturation magnetisation was reduced and the band gap increased. In each case, we found that the amount of the oxygen that had been included in the target from the precursor added to the effect of adding oxygen in the deposition chamber. It was concluded that the amount of oxygen in the target due to the precursor was an important consideration but not a defining factor in the quality of the films.

**Keywords:** PLD; target preparation; room temperature ferromagnetism; dilute magnetic semiconductor; Indium oxide; (InFe)2O3

#### **1. Introduction to the Growth of Oxide Films Using Pulsed Laser Deposition**

There is a great interest in the magnetic properties of thin oxide films for use in sensors. Pulsed laser deposition (PLD) is one of the most commonly used growth techniques [1,2]. Particular examples are pure and doped In2O3, ZnO and cuprate superconductors. A common feature of these oxides is that their magnetic and electrical properties depend strongly on the amount of oxygen that is incorporated into the film and the grain size [3–5]. PLD is a particularly versatile technique because the oxygen stoichiometry can be controlled by depositing the film in a chamber that contains some oxygen gas, and the grain size and quality of the films depend on the substrate temperature [5–7]. Almost all groups have used targets made using conventional solid-state reaction techniques to fabricate their targets.

An exception to this showed that good quality PLD films of oxides of indium could be made using a metallic target and using the oxygen pressure in the chamber to obtain an oxide film. This was done using targets that contained both metallic indium and tin that were ablated in an oxygen pressure of 7.5 Torr and a silicon substrate heated to 500 ◦C to make an NO gas sensor [8]. Films of CdO doped with indium where the target was Cd1–*x*In*x* with *x* = 0.049 were ablated in an oxygen atmosphere of 75 mTorr onto a quartz glass substrate held at 300 ◦C to fabricate CdO which is a good transparent conductor [9].

Growth using an oxide target involves grinding and sintering powders and then pressing them into a target and finally sintering again. There are several variables here, including how the grinding was performed, how many times the powders were ground and sintered and the highest temperature used to sinter the target. In many publications, these details are not given. An interesting comparison was made between the properties of PLD-ablated films of (InFe)2O3 formed when the grinding was done mechanically compared with using hand grinding using a pestle and mortar. The Fe ions that were in the films that had been ablated from a target that had been formed using mechanical grinding were almost entirely present as a secondary phase of Fe3O4 [10]. Essentially all the Fe ions were on In sites in films made using the exact same protocol of grinding and sintering but using hand grinding with a pestle and mortar [5].

Another relevant factor is the maximum temperature used to anneal the target. Good films of pure and calcium-doped yttrium iron garnet (YIG) were deposited using a target that had been made from Fe2O3, Y2O3 and, where appropriate, CaO. In this case, the target had to be annealed at a high temperature, 1200 ◦C, for 15 h because targets sintered at lower temperatures were brittle and were destroyed during laser ablation [11,12]. Good quality films were grown on a gadolinium gallium garnet (GGG) using a substrate temperature of only 500 ◦C after the films had subsequently been annealed in air at 1000 ◦C [11,12].

The annealing temperature for targets of pure Fe2O3 was important for a different reason. In this case, the target retained its orange colour when it was annealed at 500 ◦C and then could be used to grow films of maghemite by PLD at 100 mTorr. However, if the target had been annealed at 1200 ◦C in air it changed its colour to black and then could be used to get films of Fe3O4 and FeO [12].

Another situation where a target changed colour after annealing to a high temperature occurred with ZnCoO. A target was made from metallic cobalt and ZnO and was ground and sintered repeatedly. It retained its light grey colour when the maximum temperature used for annealing was 1000 ◦C but the colour changed to dark green if it was annealed at a higher temperature ~1150 ◦C. The ordered compound of Zn1–*x*Co*x*O is green (Rinman's Green) hence it was clear that in this case high temperatures are required to complete the solid-state reaction. Films that contained 10% cobalt and were of similar thickness were ablated from the targets annealed at 1000 and 1150 ◦C and were compared. It was found that the film made from the target with the 1000 ◦C anneal had a significant content of metallic cobalt present as nanoparticles that caused blocking behaviour at 30 K. The film made with the target that had been annealed at 1150 ◦C had a much larger saturation magnetisation and any nanoparticles of cobalt were too small to show blocking behaviour above5K[13].

Tuning the oxygen content in the films of pure and doped ZnO by changing the oxygen pressure in the chamber has been performed very widely. However, the oxygen content of the target can also be controlled by the precursor. To investigate the relevance of this, a study was made of films of ZnCoO using three different precursors in the targets: Metallic cobalt, CoO and Co3O4 [14]. Most previous work had used Co3O4. This study demonstrated that in this case, these different precursors produced different films even though there was no trace of the precursors in the ablated films. It also showed that using metallic cobalt as a precursor had effects beyond the concentration of oxygen and that the subtle chemistry of PLD was also affected [14].

In2O3 is an *n*-type transparent semiconductor material with a wide band gap of 3.75 eV that is in the ultraviolet (UV) region of the spectrum [15,16]. This material is an insulator in its stoichiometric form, while in its oxygen deficient form it has *n*-type doping levels that are induced by oxygen vacancies. The stoichiometry is an important factor in determining electrical properties [17,18]. In2O3 can grow in three different structures; however, all thin films that were grown by PLD grow in the cubic bixbyite structure as is seen here. In this structure, each cubic unit cell of In2O3 contains 16 formula units (80 atoms) and has a lattice constant of 10.118 Å [19,20].

In2O3 has been doped with transition metals, in particular, iron, to form (In1–*x*Fe*x*)2O3 and in this case the lattice constant decreases monotonically with increasing Fe concentration until *x* = 0.2, indicating that the maximum solubility limit of Fe ions in In2O3 lattice is approximately 20%. The saturation magnetisation, *Ms*, has also been found to increase proportionally with increasing Fe concentration, for *x* between 0.05 and 0.2 [15,21–25].

It is generally found that oxygen vacancies induce defects that are responsible for the ferromagnetism and that magnetism occurs when the Fe ions are reduced from Fe3+ to Fe2+ [15,26]. In addition, the value of *Ms* in (In0.95Fe0.05)O3 thin films has been found to be affected by the grain size, where the highest magnetisation saturation corresponds to the largest grain size implying that grain boundary magnetism is not important for these films [5].

However, there are also reports of Fe-doped In2O3 thin films that contain magnetic nanoparticles of Fe2O3 or Fe3O4 [20,25,27]. The presence of the Fe3O4 nanoparticles has been reported to enhance the room temperature magnetisation, magnetoresistance and a larger value of the coercive of ~400 Oe [10].

Previous work has considered Fe2O3 to be the obvious precursor to use with In2O3 to generate a target for the PLD because it should generate a stoichiometric target [5,10,15,19,24,26]. It is well known that if a film is ablated from a target in a high vacuum, the film will contain less oxygen than the target because some oxygen is lost in the PLD process. Hence, films are grown in different oxygen pressures so as to control the density of oxygen vacancies. In this work, we describe the effects of controlling the density of oxygen vacancies by changing the precursor used to fabricate the target as well as controlling the amount of oxygen in the growth chamber. We have made PLD films from targets that contain 5% iron using metallic iron, FeO, Fe3O4 and Fe2O3 together with In2O3 in the targets. All other conditions were kept constant.

The films were studied using X-ray diffraction to measure the change in the lattice constant with the changing density of oxygen vacancies and also X-ray absorption, X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) techniques to measure the state of ionisation of the Fe and its environment. The hysteresis loops of the films were measured at room temperature and at 5 K. Optical measurements of the absorption and the magnetic circular dichroism (MCD) were also studied. This enables us to investigate the effects on the films of adding oxygen to the target using a different precursor with that of adding oxygen to the PLD chamber. It will also indicate if there are extra chemical effects of using different targets that occur in the PLD process beyond the effects of having a different concentration of oxygen vacancies. Such effects were found in PLD films made of ZnCoO using different compounds of Co in the fabrication of the target [14].

#### **2. Fabrication of the Targets and Growth of the Films**

The targets were made using a solid-state reaction method that was performed using the following protocol which we have found to be an effective method to produce targets that could be used to grow good quality films [14]. Appropriate weights of one of the precursors, FeO, Fe2O3 or Fe3O4 and In2O3 chosen so as to give a ratio of 0.05:0.95 of Fe to In, were mixed together; the amounts used and the necessary information required to obtain these values are given in Table 1. The powders were purchased from Alfa Aesar (Karlsruhe, Germany) and had purities of 99.999% for In2O3, 99.995% for FeO, 99.998% for Fe3O4 and 99.999% for Fe2O3. The powders were hand ground for 30 min in a ceramic pestle and mortar and calcined in air at 300 ◦C for 12 h. They were then ground again for a further 30 min and sintered in air at 600 ◦C for 12 h. The procedure was repeated with the sintering temperature raised to 900 ◦C. After the final anneal, the mixture was placed in a *Specac (*Specac Ltd., Kent, England) die, which was evacuated with a roughing-pump and, using a manual hydraulic press, compressed to 25000 kPa. This produced a relatively dense, cylindrical pellet of diameter 25 mm and

thickness between 2 and 5 mm, depending upon the amount of the initial powders used. The pellet was then given a final anneal at a maximum temperature of 1000 ◦C.

**Table 1.** The weight of each material required to make targets weighing ~11 g.

Thin films of thickness of approximately 200 nm were deposited on double-side polished sapphire c-cut Al2O3 (0001) substrates that were held at 450 ◦C. The deposition used a Lambda Physik LEXTRA 200 XeCl excimer laser (Lambda Physik Lasertechnik, Goettingen, Germany) with a maximum power of 400 mJ per pulse, an operating wavelength of 308 nm, and a 10 Hz repetition rate of 28 ns pulses. The target was rotated at 60 rpm and was placed 5 cm from the substrate. We had previously checked that there was almost no difference in the films that were made using the XeCl laser compared with the, more standard, KrF laser. Three films were made from each target at each of three different oxygen pressures in the PLD chamber. The three conditions were base pressure, 2 × 10−5 Torr and oxygen pressures of 2 × 10−4 Torr and 2 × 10−3 Torr. This was to allow us to compare the effects of adding oxygen to the target from the precursor with that of adding oxygen to the PLD growth chamber.

#### **3. Results**

#### *3.1. Structural Characterisation of the Films*

The films' structural and chemical characteristics were obtained using X-ray diffraction XRD, (Rigaku Corporation, Tokyo, Japan and Bruker D2 Phaser, Coventry, UK), XANES and EXAFS techniques. These techniques gave us information on the lattice constant and grain size of the In2O3 matrix and the presence of any nanoparticles that existed in the films.

The XRD data, shown in Figure 1, were measured using Cu Kα radiation (λ = 1.5406 Å) using a θ−2θ scan. For the samples grown at base pressure, the data showed that the samples had diffraction peaks corresponding to (222) and (400) of the pure cubic bixbyite In2O3; the (006) peak is from the sapphire substrate. A small peak at ~36◦ (shown in red) indicated the presence of the secondary phase of FeO; however, no peaks from metallic iron were detected. The insets in Figure 1 show an enlarged plot of the (222) reflection; at base pressure, all three lattice constants were 10.18 ± 0.02 Å but there are real differences for the films grown at 2 × 10−3 Torr where the lattice constants for FeO, Fe3O4 and Fe2O3 were 10.17 ± 0.02 Å, 10.14 ± 0.02 Å and 10.12 ± 0.02 Å, respectively. This is in agreement with earlier results where it was found that the lattice constant increased slowly with increasing oxygen due to the elimination of isolated oxygen vacancies, but that at higher oxygen pressure it decreased rapidly due to the removal of the oxygen vacancy being accompanied by the oxidation of the large Fe2+ ion to the much smaller Fe3+ ion [15,26]. The size of the observed lattice contraction increased with the amount of oxygen in the target. Hence, the data indicated that the total amount of oxygen in the films depends on both the oxygen in the precursor as well as the oxygen in the PLD chamber.

**Figure 1.** XRD data of the Fe-doped In2O3 thin films grown from different oxide precursors at (**a**) base pressure of 2 × 10−5 Torr and (**b**) 2 × 10−3 Torr. The insets demonstrate the effect of the precursor on the position of the (222) peak.

To have a more accurate estimate of the presence of defect phases and the ionisation state and environment of the Fe ion, K-edge XANES and EXAFS spectra have been measured. The films grown at base pressure and the powder oxide standards were measured on beamline 20-BM, and the films grown at higher oxygen pressure were measured on beamline 20-ID at the Advanced Photon Source. The setups on both beamlines were similar with Si (111) monochromators providing 1 eV energy resolution at the Fe K edge. The measurements were made at room temperature at a glancing angle of ~5◦ with the X-ray polarization normal to the surface of the films. Multielement solid-state detectors (4 element silicon drift detector on 20-ID and 13 element Ge detector on 20-BM) were used for fluorescence detection, and the samples were spun at a few Hz to avoid Bragg reflection interference from the single-crystal substrates. Typically, 4–8 scans were averaged for improved signal to noise. Data were analysed using the Demeter analysis package [28].

In the XANES spectra, as shown in Figure 2, the signals from wüstite (FeO), magnetite (Fe3O4) and hematite (Fe2O3) have been plotted alongside Fe-doped In2O3 films to be used as references. Figure 2a displays the data from the samples grown at base pressure and indicates an absorption at ~7117 eV (marked with an arrow) that is at a lower energy than for wüstite. This means that they all contain a small percentage of metallic iron. Such results are caused by the increased number of oxygen vacancies that are generated by PLD at base pressure [29] and all evidence of metallic iron has vanished from the films made at 2 × 10−4 Torr and 2 × 10−3 Torr. The XANES data for the films deposited at higher oxygen pressure, 2 × 10−3 Torr, are close to that of hematite, Fe2O3, indicating that most of the Fe ions are in the state Fe3+ although a small fraction of the Fe ions may be present as Fe2+.

**Figure 2.** K-edge X-ray absorption near edge structure (XANES) spectra of reference compounds of metallic Fe, FeO, Fe3O4 and Fe2O3 and the Fe-doped In2O3 films grown from different precursors at (**a**) at base pressure of 2 × 10−5 Torr; where an arrow at 7117 eV indicates an additional absorption and (**b**) higher partial oxygen pressure of 2 × 10−3 Torr.

The environment of the Fe ions is obtained from an analysis of the Fourier transform of the EXAFS and the results are shown in Figure 3. The results for the films grown at base pressure are shown in Figure 3a and are compared with the EXAFS spectrum from a sample of Fe2O3-doped In2O3 sample that is believed to be pure substitutional [5]. All of the data shows a strong peak near *R* = 1.6 Å from near neighbour oxygens. Note that the transforms are not phase corrected, so the peaks are shifted ~0.3 Å lower from their actual distances. The spectra from the films that were grown at base pressure have similar peaks in the region *R* = 2–4 Å as the fully substitutional spectrum (shown in red) except near *R*~2.1 Å where they show small additional peaks that are likely characteristic of Fe metal. If the metallic fraction is very small, it is difficult to detect it in diffraction. Attempts at fitting with a metal site combined with a substitutional site were only moderately successful. A good fit was achieved with about 12% of the doped Fe in the metallic environment, but the substitutional site parameters had to be modified more than seems reasonable to accommodate the Fe. This indicates the possibility of a third type of Fe oxide site, in agreement with the XRD where a small signal from FeO was also detected. Unfortunately, the data range was such that it is difficult to reliably fit a three-site model. The reduction in the intensity for 2 ≤ *R* ≤ 3 Å, also suggests the presence of some Fe oxide secondary phase in addition to the metallic Fe clusters.

Detection of an impurity phase by XRD depends on the ability to measure the square of the concentration. In this case, this is given by the percentage of Fe in the whole sample, 5%, and the percentage of these atoms that are in a metallic environment, about 12%. These combine to give a percentage of metallic Fe in the sample that is about 0.6% which was not measurable.

The data shown in Figure 3b are from the samples grown at 2 × 10−3 Torr. A plot of a reference sample of hematite has been included because the XANES data from the films had indicated that all the iron was in the Fe3+ state which is also characteristic of hematite. These data show that the atomic arrangement in the films is very close to that expected for Fe ions substituted on the In sites and distinct from that of hematite. At higher oxygen pressures, the Fe ions appear to be substitutional for all the targets and show no evidence of any metallic iron or any iron oxide. There are some differences in the edge data between our sample and the reference sample that may be due to the result of better structural order in our samples. While the basic structure of the peaks looks similar, there is an increasing difference in the height of the peaks at larger distances that could be a characteristic of disorder. The In2O3 has two different In sites and the disorder arises if the Fe substitutes randomly on both sites [15,27].

**Figure 3.** X-ray absorption fine structure (EXAFS) Fourier transform of Fe2O3 and substitutional Fe2O3-doped In2O3 deposited at base pressure as reference compounds and the Fe-doped In2O3 films grown from different precursors at (**a**) base pressure of 2 × 10−5 Torr and (**b**) O2 pressure of 2 × 10−3 Torr.

In summary, we find evidence of defect phases, metallic iron from the XANES and FeO from the XRD and the EXAFS in films grown at base pressure. The results of the XANES and the EXAFS measurements of films grown with oxygen in the chamber indicated that substantially all the Fe3+ ions were situated on In3+ sites.

#### *3.2. Magnetic Properties of the Films*

Magnetic hysteresis loops were taken at 5 and 300 K for the substrates and all the Fe-doped In2O3 films using a Quantum Design SQUID magnetometer (San Diego, CA, USA). It was found that all the films displayed room temperature ferromagnetism; examples of the loops obtained are shown in Figure 4 and the values of *M*s and *H*c measured at room temperature for the different precursors and oxygen pressure in the PLD chamber are summarised in Table 2. A magnetic field of 10,000 Oe was applied parallel to the plane of the film during the magnetisation measurements. The diamagnetic contribution from the sapphire substrate was subtracted, as was the paramagnetic contribution from the film from the data shown in Figure 4.

**Figure 4.** (**a**) and (**b**) are respectively the magnetic hysteresis loops measurements at 5 and 300 K for the Fe-doped In2O3 films from different oxide precursors at a base pressure of 2 × 10−5 Torr, (**c**) shows the room temperature data for films that were made with Fe metal in the precursor. The diamagnetic and paramagnetic terms have been subtracted from all the data shown here.

The paramagnetic contribution from the film, seen at 5 K, was consistent with it being due to free spins of all the Fe3+ ions because the value of *pe*ff was found to be 4.5 ± 0.3 compared with the expected value for Fe3+ of 4.9 [30]. The observed strong temperature dependence of the saturation magnetisation was observed previously in films of Fe-doped In2O3 that had semiconducting behaviour [3,15,31]. Part of the magnetisation observed from the films deposited at base pressure could be due to the 12% of the Fe ions that were in a metallic environment as observed by EXAFS leading to a metallic concentration of about 0.6%. If each of these contributed 2.2 μB to the bulk magnetisation, this would contribute about 1.3 emu/cm3 to the magnetisation. This is comparable to the difference between the

magnetisation observed for films grown at base pressure and those grown at 2 × 10−4 Torr for the films grown with the oxide precursors.

Previous results had found that oxygen vacancies and Fe2+ ions were necessary for ferromagnetism to be observed in Fe-In2O3 and these results are consistent with this earlier work [3,31,32]. This pattern was seen for all films and all oxygen content because it was found that both the saturation magnetisation and coercive field decreased with oxygen content whether the oxygen was in the target or in the PLD chamber. The decrease in magnetisation for added oxygen was larger for the films deposited at base pressure. The large value of *Ms*, seen only at base pressure, may be due to the existence of metallic iron as seen by XANES as well as a larger number of oxygen vacancies [3,31,32]. The coercive field of the films deposited at base pressure from the FeO target was increased significantly at 5 K compared with that measured at 300 K, leading to the deduction that blocked magnetic nanoparticles, of probably Fe metal, existed at low temperatures in that film. This increase was not seen for the films deposited at higher pressure. The magnetisation of the films made from the target that contained metallic iron as the precursor showed a stronger dependence on oxygen content than the films made from the oxide precursors. Interestingly, the coercive field seen at 5 K for the film grown from the Fe metal target at base pressure was higher than with those grown from the oxide targets grown at base pressure. This implies that if, as expected, the film grown with a Fe-target does contain a larger percentage of metallic iron, the nanoparticles are so small that their blocking temperatures are close to 5 K, or below, whereas significant blocking of nanoparticles has occurred for the film ablated from the target that had been made with FeO.

Temperature-dependent plots of the magnetisation were measured under the conditions of zero field cooled (ZFC) and field cooled (FC) to investigate further the relative importance of nanoparticles. This magnetisation was obtained for all the samples grown from FeO, Fe3O4 and Fe2O3 precursors and deposited at base pressure; this was the condition where the XANES measurement had indicated the presence of about 12% of the iron atoms in a metallic environment. A magnetic field of 100 Oe was applied in parallel to the plane of the samples [33–35]. The diamagnetic contribution from the sapphire substrate was subtracted from all ZFC and FC curves shown in Figure 5. The separation of the ZFC and the FC curves is due to the increase of the anisotropy field to become comparable or larger than the measuring field, 100 Oe, as the temperature is reduced. If the magnetisation had been dominated by nanoparticles, the curves should vary as 1/*T* in the reversible regime, but this is not observed here.

The FC/ZFC curves shown in Figure 5a,b for the films made from oxide precursors and grown at base pressure are consistent with the increase in the coercive field at the temperature measured at 5 K as given in Table 1. The large coercive field observed at 5 K for the film grown from the FeO could be due to shape anisotropy of the metallic inclusions but even in this case, the 1/*T* dependence in the reversible region was not observed, indicating that the magnetic contributions from the nanoparticles are not dominating the overall magnetisation.

**Figure 5.** Field cooled (FC) and zero field cooled (ZFC) magnetisation curves of the Fe-doped In2O3 from Fe3O4 and Fe2O3 precursors in (**a**) and from FeO precursor in (**b**) where all samples were grown at a base pressure of 2 × 10−5 Torr.

The increase of the magnetisation below 50 K is a characteristic of all DMS materials. This behaviour arises from isolated paramagnetic ions which are not contributing to the long-range ferromagnetic order. Existence of these ions was already discussed because they give rise to a paramagnetic contribution to the hysteresis loops [30].

#### *3.3. Optical Absorption*

The optical properties of the Fe-doped In2O3 films were investigated by carrying out transmission and reflection measurements at room temperature. From these measurements, absorption data were obtained to gain an insight into the electronic structure and to estimate the density of gap states and the band gap of the films.

The optical properties of this material are sensitive to different targets and film preparation parameters, including the amount of oxygen, the following results will show the effect of changing the oxygen content. Figure 6 illustrates the absorption data at energies close to the band edge for all the Fe-doped In2O3 films grown at the base and different oxygen pressures. In doped In2O3 there are two dominant effects that can change the band gap. Isolated oxygen vacancies are donors and will be ionised to increase the band gap due to the Burstein-Moss effect, however, a lattice contraction will increase the band gap. Both effects are relevant here. The values of the band gap are summarised in Table 3. At low oxygen pressure, 2 × 10−5 Torr, the films have essentially the same lattice constant and the band gap is highest for the films with the lowest amount of oxygen in the target due to the Burstein-Moss effect. At the higher oxygen pressure, 2 × 10−3 Torr, the lattice contraction for the films containing the most oxygen is the dominant effect in determining the lattice constant.

All the spectra show a substantial amount of absorption below the energy gap due to energy states in the gap. We note that the highest density of gap states occurs for the three films grown at base pressure, which were known to contain about 12% of the iron atoms in a metallic environment.

**Figure 6.** Absorption data of Fe-doped In2O3 samples grown from FeO, Fe3O4 and Fe2O3 precursors deposited at a base pressure of 2 × 10−5 Torr and the two higher oxygen pressures of 2 × 10−4 Torr and 2 × 10−3 Torr.

#### *3.4. The Magneto-Optical Properties*

The MCD spectra for all Fe-doped In2O3 samples were measured in the energy range between 1.7 and 4 eV at room temperature in Faraday geometry using an applied magnetic field of 18000 Oe, as displayed in Figure 7. The MCD is a very powerful technique because it indicates the amount of spin polarisation that is present in the quantum states that are involved in transitions at a particular energy [36]. The MCD signal from the sapphire substrate has been subtracted from the data shown in Figure 7.

**Table 3.** Summary of the band gap values of Fe-doped In2O3 thin films deposited at the base and higher oxygen pressures.

The results taken at base pressure are shown in Figure 7a; these are characteristic of films that contain metallic iron where the MCD may be calculated using the Maxwell–Garnett theory [5,15,37]. The signals indicate that the most metal is in the film made from the FeO target and the least in the one made from the Fe2O3 target, but in both the percentage of the volume occupied by metal is small, approximately 0.5% or less. In contrast, there is no sign of any metallic iron seen in the MCD spectra of the films made at the higher oxygen pressure shown in Figure 7b, as expected from the XANES results shown in Section 3.1. The MCD spectra varied between positive for the film with the lowest oxygen content, FeO-In2O3 grown 2 × 10−4 Torr, to negative for the film with the largest amount of oxygen, Fe2O3-In2O3 grown at 2 × 10−3 Torr, as the oxygen content was increased. It had been found earlier that the MCD was positive for films with a high density of carriers produced by oxygen vacancies and small or negative for those in the semiconducting regime [15]. These results are also consistent with the values of the saturation magnetisation obtained from the magnetic hysteresis loops measured by the SQUID shown in Table 1.

The dip observed in all the spectra shown in Figure 7b just above 3.4 eV and below the band gap energy stated in Table 2 is typical of magnetic oxide semiconductors. It arises from transitions from the valance band to empty donor states of oxygen vacancies situated below the conduction band edge and is a clear indication that these donor states are spin polarised [35]. The absorption from these states is seen in Figure 6 in the region of about 0.25 eV below the band gap.

**Figure 7.** Magnetic circular dichroism (MCD) spectral shapes of the Fe-doped In2O3 samples deposited from different precursors at (**a**) base pressure and (**b**) at 2 × 10−4 Torr shown with black, red and green symbols for FeO, Fe3O4 and Fe2O3, respectively and at 2 × 10−3 Torr with blue, turquoise and pink symbols for FeO, Fe3O4 and Fe2O3, respectively.

#### **4. Discussion**

In this work, we studied a range of films that have differed in two aspects: The amount of oxygen in the PLD chamber and the precursor that was used to add Fe ions to the target material. We anticipated that films that were made with FeO in the target would contain less oxygen than those that were made with Fe3O4, which in turn would have less oxygen than those made with Fe2O3, however, we speculated that there may be subtle questions of chemistry of the PLD process that come into play, as we found in Co ions incorporated in ZnO [14].

The aim of this work was to see if the extra oxygen that is incorporated into the target enters the films in a similar way as the oxygen included in the PLD chamber. We investigated this by keeping all other variables constant. All the films had the same percentage of iron (5%), the same procedures for mixing and annealing the targets, the same substrate temperature and, as far as possible, the same thickness of the films. The processing of the targets was done in air, so it was interesting to observe that the amount of oxygen in the target still depended on the precursor and was not equalised during the process of fabrication.

The three precursors have different magnetic properties: FeO and Fe2O3 are antiferromagnetic, or very weakly ferromagnetic, whereas Fe3O4 is strongly ferromagnetic. Hence, it was important to check if any of the Fe3O4 precursor had survived in the films and the XAFS data showed clearly that it had not. Nor was there any suggestion that the magnetic properties of the film made with this precursor were significantly inconsistent with the other films.

We had evidence of defect phases of both metallic iron and FeO appearing in all our films that had been grown at base pressure. The appearance of FeO in these films occurred for all three oxide precursors as is clear from the XAFS shown in Figure 2a and was a consequence of the low oxygen pressure and not dependent on FeO being in one of the targets. Figure 8a shows the change of the magnetisation measured at room temperature as a function of the oxygen pressure for all of the films. In this case, the amount of oxygen in the target and the PLD chamber produced effects of similar magnitude. It is clear that the largest magnetisation in films without metallic iron was made from a

target that had been produced using FeO. This is interesting because the precursor of choice had been assumed to be Fe2O3 which was found to be the worst performing precursor in this study.

**Figure 8.** The dependence of (**a**) the band gap and (**b**) the saturation magnetisation on the oxygen pressure.

The results of this study are summarised in Figure 8 and Table 1. These show that as the level of oxygen in the PLD chamber is increased the energy of the band edge increases as shown in Figure 8a and the saturation magnetisation reduces as shown in Figure 8b. These results are in agreement with earlier work that deduced that the magnetisation in (In1–*x*Fe*x*)2O3 is due to oxygen vacancies and the compensating Fe2+ ions that are removed by the addition of oxygen [15].

The measurements described here give a coherent account of PLD films made with iron oxide precursors and ablated in different oxygen pressures. The measurements of the lattice constant, XANES and EXAFS spectra, band gap and magnetic measurements were combined to give a clear description of these films. The results fit the general pattern that the oxygen in the target, generated from the precursor, had a similar effect as adding oxygen to the PLD growth chamber. The films grown at base pressure contained some metallic iron as indicated by X-ray absorption and larger coercive fields at 5 K, however, the density of oxygen vacancies was smaller for the precursors, with more oxygen in the target as indicated by the band gap. At higher oxygen pressures, both the density of isolated oxygen vacancies and the density of Fe2+ ions were reduced with corresponding drops in the magnetisation, more details are in [38]. The magnetism of the films grown with metallic Fe decreased more rapidly as oxygen was added to the growth chamber. More work should be done on this interesting system.

It has been customary to fabricate targets using Fe2O3 mixed with In2O3 because it was assumed that this would naturally be a combination that would be best suited to incorporate the Fe into the In2O3 lattice. The work done here suggests that FeO would be a better choice because films made with this precursor have a higher magnetisation than those made with Fe2O3.

**Author Contributions:** Conceptualisation H.B.A. and G.A.G.; Methodology, H.B.A., A.M.A.S., S.M.H., A.M.F. and M.S.A.; Validation, H.B.A. and G.A.G.; Investigation, H.B.A., A.M.A.S., F.-X.J., S.M.H. and K.Y.M.; Resources, H.B.A., G.A.G., S.M.H. and M.S.A.; Writing—original draft preparation, H.B.A.; Writing—review and editing, G.A.G. and M.S.A.; Supervision, G.A.G., A.M.F.; Project administration, G.A.G. and M.S.A.

**Funding:** This research was funded by Saudi Cultural Attaché-London, UK Engineering and Physical Sciences Research EP/D070406/1, Advanced Photon Source, an Office of Science User Facility operated for the US Department of Energy (DOE) Office of Science by Argonne National Laboratory and was supported by the US DOE under Contract No. DE-AC02-06CH11357 and the Canadian Light Source and its funding partners and King Abdulaziz City for Science and Technology (KACST), Saudi Arabia.

**Acknowledgments:** H.B.A. acknowledges the receipt of a studentship from the Saudi Cultural Attaché-London. The SQUID and MCD measurements were taken on apparatus initially funded by the UK Engineering and Physical Sciences Research EP/D070406/1. This research used resources of the Advanced Photon Source, an Office of Science User Facility operated for the US Department of Energy (DOE) Office of Science by Argonne National Laboratory and was supported by the US DOE under Contract No. DE-AC02-06CH11357 and the Canadian Light

Source and its funding partners. In addition, resources for target preparation provided by King Abdulaziz City for Science and Technology (KACST), Saudi Arabia.

**Conflicts of Interest:** The authors have no conflicts of interest.

#### **References**

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

#### *Communication*


Section 2 Children and Yoga

## **Chapter 3** Benefits of Yoga on Children

*Mei-Ling Lin*

## **Abstract**

This chapter begins with an introduction of yoga and available yoga programs or curriculum for children of all ages and all abilities. Next, it summarizes the theoretical frameworks that support the investigation of the benefits of yoga, with an emphasis on the sensory integration theory. Third, this chapter draws on empirical studies from multiple disciplines to pinpoint the physical, mental, and social benefits of yoga on children with and without special needs. To conclude this chapter, case examples are utilized to showcase the implementation of yoga activities in school and group settings. Suggestions for researchers and practitioners who work with children are discussed as well.

**Keywords:** yoga, sensory integration, children, health benefits, well-being

## **1. Introduction**

Yoga is a mind-body practice that originated in ancient India and has been gaining popularity worldwide due to its numerous physical, mental, cognitive, and spiritual health benefits [1]. While practicing yoga, individuals are instructed to focus their attention on their body posture, breathing, emotional awareness, and meditation [2]. In recent years, yoga has become increasingly popular in children and youth populations. Yoga programs designed for young learners often incorporate storytelling, games, music, and imagination to make the yoga practice fun and engaging. See **Table 1** for a listing of children's yoga programs that are available in the United States.

## **2. Conceptualizing the benefits of yoga from sensory integration theory perspectives**

The sensory integration (SI) theory and the definition of sensory integration (SI) were formulated by Dr. Jean Ayres as "the neurological process that organizes sensations from one's own body and from the environment" (p. 11) [4]. Individuals learn knowledge and skills by reading, listening, speaking, and writing or manipulating [5]. The SI theory postulates that learning, or adaptive behaviors, is dependent on the ability to process and integrate sensation and use it to regulate emotions and plan movements. Practicing yoga, from the perspectives of the SI theory, is a learning process; competently and safely performing yoga is viewed as an adaptive behavior. See **Figure 1** for a schematic representation of practicing yoga based on the SI theory.

#### **Table 1.**

*Children's yoga program and curriculum in the United States.*

#### **Figure 1.**

*A schematic representation of practicing yoga based on the SI theory. Adapted from Figure 1-1 A schematic representation of the learning component of SI theory [6].*

#### *Benefits of Yoga on Children DOI: http://dx.doi.org/10.5772/intechopen.112105*

While practicing yoga, a child is presented with visual information about certain yoga poses from cards/pictures or from yoga instructor's demonstration. The instructor may supplement their demonstration with verbal explanations or guided imagination (auditory information). To follow and successfully perform the yoga poses, the child then integrates the visual and auditory inputs with their ability to plan and use two aides of their body in a coordinated way, their ability to form the spatial relationship of different body parts in their mind (i.e., body scheme), and their ability to sense the internal signal from their body to breath. According to the SI theory, the bilateral coordination skills, body scheme, and breathing are hypothesized to be rooted in individual's vestibular, proprioception, tactile, and interoception processing abilities [6].

Notably, when a child is trying to imitate and perform yoga poses, he/she is obtaining sensory feedback from their body and their surrounding environment, specifically, the feedback from their body about their head position and balance (vestibular), the spatial relationship of different body parts (proprioception), and their breath (interoception). The feedback from their surrounding environment may include, but not limited to visual, auditory and tactile inputs (e.g., touching a yoga ball). The SI theory also postulates that the sensory feedback generated in the context of a just right postural or movement challenge contributes to improved sensory integration/processing, thereby enhancing learning and adaptive behavior [6].

So, upheld by the SI theory, the benefits of yoga may be contributed directly by the sensory feedback the child's body obtains during the practice of yoga and improved sensory processing following the practice of yoga. Proprioception is defined as perception or awareness of the position and movement of the body [7]. In the neuroscience literature, proprioceptive feedback, obtained from proprioceptive receptors located in muscle spindles and joints, have been clinically observed to have a calming effect [8–10]. This may explain the emotional or psychological benefits associated with practicing yoga. The vestibular system enables the perception of balance and provides information about body position, facilitating quick compensatory movements in response to both internally initiated and externally applied forces [11]. Together, vestibular and proprioceptive processing contribute to the coordination of head and body movement in space, the development of bilateral coordination, and the development of postural control (e.g., equilibrium). This may explain the physical health benefits of practicing yoga. Also, both proprioceptive and vestibular inputs have been linked to increased arousal levels [12]. This may explain the cognitive benefits (i.e., attention and learning readiness) of practicing yoga. The mental, physical, and cognitive benefits of yoga practices jointly contribute to an individual's self-awareness and social interaction with other people at different developmental stages.

## **3. Understanding the benefits of yoga for children from scientific evidence**

Since yoga is considered a mind-body practice and often embedded in mindfulness practices and mindfulness-based interventions, and the deep breathing technique is an integral part of yoga practices, the findings from empirical studies that investigate the effects derived from deep breathing techniques as well as mindfulness and yoga practices are summarized in the following.

The previous research findings have revealed that instructing third- and fifthgrade students to engage in deep breathing techniques prior to tests led to reduced test anxiety and enhanced test performance [13, 14].

Mindfulness practice involves cultivating a state of heightened awareness attained through nonjudgmental attention to the present moment [15]. Across adolescent, adult, and geriatric populations, mindfulness practice has demonstrated associations with a range of benefits encompassing interpersonal aspects (such as fostering healthy relationships), emotional well-being (including decreased loneliness, stress, and anxiety), as well as intrapersonal advantages (such as the development of empathy, compassion, self-efficacy, attention, and executive functioning) [16–21]. Systematic reviews and meta-analyses conducted on mindfulness-based interventions implemented in school settings have established a positive correlation between mindfulness practices and enhanced mental health outcomes. These outcomes include reductions in stress, anxiety, and depression, as well as improvements in attention [22, 23].

Yoga offers numerous benefits for children with all abilities. Research has indicated that engaging in yoga serves as an effective intervention in mitigating anxiety, depression, and associated symptoms or behaviors among children and adolescents [24–26]. For typically developing children, yoga can also promote physical and mental health [27], as well as improve emotional regulation and self-awareness [28–30]. The study conducted by Morena-Gomez and Cejudo on kindergarten students revealed further advantages of mindfulness-based programs, which encompassed practices such as meditation, mandalas, and body awareness activities. These programs were found to contribute positively to overall child development, nonverbal development, and visual perception, while concurrently reducing maladaptive behaviors [31]. The above evidence support the use of mindfulness-based programs and yoga to enhance children's confidence, self-esteem, and social skills, while also providing an outlet for creativity and self-expression.

For children with special needs, yoga practices can help improve motor coordination, increase strength and flexibility, reduce anxiety and stress, and enhance overall well-being. For example, children and adolescents diagnosed with attention-deficit hyperactivity disorder (ADHD) have demonstrated improved attention and social behaviors following the participation in the mindfulness-based interventions (including yoga) [32]. Additionally, yoga has shown promise as a potential strategy for reducing stress and anxiety, enhancing quality of life, and improving lung function in children and adolescents diagnosed with asthma [33]. Moreover, a multicomponent program that involves yoga, dance, and modified relaxation response program has showed promising outcomes in improving behavioral and some core features of autism spectrum disorders for children aged 3–16 years [34]. Overall, there is gaining evidence to support the incorporation of yoga in treating children and adolescents with depression, sleep disorders, and as an augmentation therapy for pediatric populations with schizophrenia and ADHD [35].

## **4. Methods**

Given the health benefits associated with yoga and mindfulness practices, the author conducted a needs assessment and developed a school-based mental health promotion program to address children's mental health needs in a US-Mexico border community. In this section, the community's mental health needs are presented first. Then, the group-based program activities are described in greater detail. Third, the lessons learned from program implementations are discussed; future directions for yoga research and practices are presented.

## **4.1 Mental health needs in schools at the US-Mexico border community**

School-age children living in an US-Mexico border city are facing multiple stressors in their school and home lives. In the state of Texas, third-grade to twelfthgrade students need to take the State of Texas Assessments of Academic Readiness (STAAR) test every spring semester. The increasing level of academic stress derived from numerous practice tests, quizzes, and exams in preparation for the STAAR test is noticeable and sensible. At the time of the needs assessment, no social emotional learning (SEL) curriculum was formally taught to students to recognize their own and others' emotions and to use stress management techniques to positively face and deal with stress and anxiety.

Notably, the elementary school served 535 students in kindergarten through sixth grade, predominantly children living in Hispanic families (92%) with low socioeconomic conditions (78%). Stressors associated with disadvantaged living conditions, along with stressors unique to the Hispanic population, such as language barriers, perceived discrimination, mental health stigma, and higher risks of having inconsistent health insurance coverage and unmet mental and behavioral needs, all indicate a need to improve mental health awareness, literacy, and access in this population [36].

To respond to the school's mental health needs, occupational therapy faculty and students from the University of Texas at El Paso collaborated with the school team to develop and pilot-test a "Tools for stress" workshop to lay the foundation for developing a school-wide mental health promotion program for the elementary school. The author's intention is multi-faced, including equipping elementary school students with evidence-supported coping strategies to address stress and anxiety, documenting scientific evidence to support the implementation of school-based mental health promotion programs, and establishing long-term university-school collaborative relationships.

## **4.2 Case 1: "Tools for Stress" workshop**

"Tools for Stress," a 45-minute workshop for kindergarten through fourth-grade students (N = 382), was designed to fit into the school's career day schedule in which the speakers from the community come to speak their job or profession and answer students' questions. There were four classes per grade level, and each class had around 20 students [37].1 On the date the workshop is held, each grade level would come into the school gymnasium that was set up to accommodate all the program activities. The workshop opened with questions such as, "what is stress?" and "how do you feel and what do you do when you are stressed?" to survey and further students' understanding of physical, emotional, and behavioral signs of stress. Onsite translation support was provided for non-English learners. The sequence of program activities all in a group format is presented in **Table 2**.

This workshop concluded with an anonymous survey to gain student's feedback (e.g., "how much did you like the activities?" and "how confident would you be to use the activities the next time you feel stress?"). Overall, this program obtained an overwhelming positive response from students. Of 364 valid surveys collected from participating students, 85% liked the yoga and deep breathing exercises, 95% liked the sensory bottle they made, and 82% indicated they were confident and competent about using the calming strategies in the future when feeling stressed. The school

1 The fifth and sixth graders had schedule conflicts that precluded their inclusion.

*The "Tools for Stress" workshop overview.*

#### *Benefits of Yoga on Children DOI: http://dx.doi.org/10.5772/intechopen.112105*

counselor has continued to reinforce the strategies introduced in the workshop with students in 1:1 counseling session. However, the counselor also mentioned challenges to incorporate yoga and other mindfulness-based strategies into each classroom and an already-packed school daily schedule. The school administration requested that this program be continued and expanded for both students and teachers and broadened to include workshops for families.

### **4.3 Case 2: The school-wide mental health promotion program**

In the fall of 2019, based on the feedback collected from the "Tools for Stress" workshop and the synthesis of scientific literature, occupational therapy faculty and students from UT-El Paso design a mental health promotion program and conduct an empirical study to explore its outcome on fifth and sixth graders' perceived ability to handle negative emotions (i.e., emotional self-efficacy, ESE) and their perceived levels of satisfaction with the program. This program consists of four in-person instructional sessions that integrate the existing evidence and incorporate specific lessons from the Zones of Regulation curriculum [39]. Every session was carefully planned to have a duration of 45 minutes and took place once a month within the school's indoor gymnasium during the physical education (PE) class time. The sessions were facilitated by second-year OT students, closely supervised by three OT faculty members, along with the participation of the school counselor and the school nurse. See **Table 3** for the program overview.

Results obtained from a sample of 100 students (39 boys and 60 girls, with 1 case of missing data; 57 fifth graders and 43 sixth graders) indicate that, for the entire group, there are no statistically significant differences in emotional self-efficacy (ESE) ratings before and immediately after the implementation of the mental health promotion program (t(84) = −1.08, *p* = .29). However, noteworthy findings emerge when examining the pretest and posttest scores. Students with lower ESE ratings before the program demonstrated improved ESE ratings after program participation (t(46) = −3.258, *p* = .00), while those with higher initial ESE ratings experienced a decline in ESE ratings (t(37) = 1.98, *p* = .06). No significant differences were observed between boys and girls or between fifth and sixth graders regarding ESE ratings before and after program implementation. Overall, more than 60% of the program participants expressed a neutral to positive attitude toward the program activities. Among all the program activities, students favored mandala coloring the most, followed by slime making, deep breathing, and yoga, respectively. Approximately 70% of the program participants expressed feeling both competent and confident in utilizing one of the calming tools they had learned during the program when facing future stress.

### **4.4 Discussion**

Suggestions are made based on the two case examples for researchers and practitioners who consider implementing yoga programs or curriculum to address the social emotional needs of school-age children.

First, the collaboration among parents, teachers, and mental health providers (e.g., counselors, psychologists, and occupational therapists) is the key to the successful program implementation and the most optimal children outcome. Outside of the "Tools for Stress" workshop, the OT faculty set a booth at the school health fair to provide educational materials to increase parental awareness of family

#### **Table 3.**

*Mental health promotion program overview [40].*

mental health and to facilitate healthy ways to manage stress using the tools and strategies their child learned from the workshop. For teachers and paraprofessionals, two 1-hour workshops introduced evidence-informed stress management techniques (i.e., breathing exercises, yoga stretches, using a sensory board that included various textures) that could be implemented in the classroom to support students' self-regulation and address students' emotional and behavioral challenges. Under the circumstance that all the stakeholders are aware of the importance and benefits of yoga, children can be given provided numerous opportunities to practice yoga. And the benefits of yoga can be maximized and carried over to different environments.

Second, the timing of yoga instruction should allow students to immediately apply their learning to real-life situations. A comparison of the workshop satisfaction survey results and the research study's program satisfaction survey results showed that 85% of kindergarten to fourth-grade students like yoga and deep breathing. Yet only 27% of and 40% of fifth and sixth graders like yoga and deep breathing correspondingly. Additionally, the satisfaction ratings of the workshop activities were higher among younger elementary school students compared to the satisfaction levels of fifth and sixth graders in the implemented program. One possible reason for this

### *Benefits of Yoga on Children DOI: http://dx.doi.org/10.5772/intechopen.112105*

disparity in the satisfaction survey outcomes is that younger students could immediately perceive the benefits of the calming tools they learned when they took the STAAR test. In contrast, older students completed the survey during the fall semester when no STAAR testing was conducted, which could explain their relatively lower satisfaction levels.

Third, early introduction of yoga and cultivation of child's interest in yoga are recommended. It is observed that younger students demonstrated better response and acceptance toward yoga and other program activities compared to older students. The developmental stage of middle childhood is characterized by the emergence of self-autonomy and a significant influence of peers within social networks. That is, older elementary school-age children may be more susceptible to peer pressure compared to their younger counterparts. As a result, they may be more inclined to mimic their peers' responses to stress and anxiety rather than adopting the strategies and techniques taught by adults. Since the motivation and the interest to learn yoga is the foundation for the continuation of practicing yoga, the future design of yoga programs or curriculum should shed more emphasis on early childhood populations.

Last but not the least, the integration of technology into yoga instruction and learning holds great potential for both practitioners and researchers. Utilizing webor mobile-based applications, such as *Adventures in Emotional Literacy* developed for elementary school students (3C Institute, n.d.), offers the advantage of flexibility in terms of time and location to students to acquire emotional literacy and coping skills. This approach allows instructors to maximize in-person teaching time and to enable students to put into practice the knowledge and skills acquired through the e-curriculum. Gathering information such as program satisfaction, frequency of application use, and knowledge gained before and after program implementation can be easily achieved through web-based platforms and learning management systems.

## **5. Conclusion**

To conclude this chapter, key information is highlighted as follows.

## **Acknowledgements**

I want to express my sincere gratitude to the UTEP College of Health Science, Occupational Therapy Program, faculty, and Classes of 2019 and 2020 students for the participation and ongoing support to this research project. I also want to acknowledge the REL Washington Elementary in El Paso, Texas, for their enthusiasm and dedication to this collaborative project and school mental health.

## **Conflict of interest**

The author declares no conflict of interest.

## **Appendices and nomenclature**

See sample yoga script.

## **A. Sample yoga script**

Stand tall like a mountain (mountain will be the resetting posture/resting pose) feet firmly planted down on the ground, arms out, palms out, strong finger reaching to the ground.

Breathing in and out of your nose—as your belly goes in and out. Mindful breathing as you breathe in for 1, 2, 3 and out 1-5.

 (Sometimes if you have a bad day, it's good to plant your feet firmly on the ground and take a few deep breaths)

Slowly bring your hands to your heart, bring your elbows out to your side, palms facing each other. Press your hands as hard as you can for 1, 2, 3 and relax (3x's)

Relax your arms down at your side, shake it out

Come back to mountain, stand tall and strong like a mountain, and take 3 deep breaths (guided), see how still you can be…

Now bring your arms out to your side, lift them up overhead like you're reaching for the sun/sky.

When your arms and hands are up in the sky, interlace your fingers and make a 'steeple', 'water gin' …etc. Relax the shoulders down and reach your steeple up.

Release your arms, shake them out.

 Twist to the right and left, shooting your star around while keeping your legs firmly planted on the ground.

Stand firm on your L leg and lift your R leg up and back.

Grow your tree, blow in the wind, etc.

Release and shake it out.

Come back to mountain and prepare to do the other side.

Bring your L foot into your L hand behind you.

Release, and shake it out.

Come back to mountain and take a deep breath in and exhale loudly.

Bring your hands to your waist, stand tall like a superhero.

While in superhero—take three deep breaths in and out your nose.

Relax arms down at your side.

Bring your hands back to your heart and say, "I AM AWESOME."

Then turn to your friends and say, "YOU ARE AWESOME!"

Then we end our practice with, "The awesome in me recognizes the awesome in you! Namaste"

## **Author details**

Mei-Ling Lin The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA

\*Address all correspondence to<EMAIL_ADDRESS>
© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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**6. Cultural competence**

into account characteristics shared by the subgroup's members" [19]. The concept is based on the assumption that the group has enough characteristics in common to make a single

Cultural tailoring, on the other hand, is any combination of information or change strategies intended to reach **specific individuals** based on characteristics that are unique to them related

Historically, only a few health promotion programs made serious attempts to develop culturally appropriate strategies to meet the needs of target populations. But with increasing evidence that health promotion programs and materials will be more effective when cultural factors are taken into consideration health service managers seem to be gradually changing their approach. Recently, most interventions have been based on assumptions of culture. While this may be an improvement of the past, much more precision in culture interpretation

Questions have been raised as to whether it is logical to expect a consideration of what is common to a group while still laying emphasis on individual peculiarities. In fact, some authorities have referred to the idea as a paradox [4]. In practice, it is probably unnecessary to expect that one will have to choose between cultural tailoring and cultural targeting when designing and delivering a health service. Instead, it is more important to carefully decide to what extent both approaches need to be combined in order to get the most benefit each offers. There will be situations when the health needs within a target population are so similar that identifying subgroups becomes difficult. In such situations, health tailoring loses its necessity,

A basic understanding that must be borne in mind is that while a group may have certain characteristics in common (beliefs, values, attitudes, etc.), individuals within the group have imbibed these ideas to different extents, a few not at all. A typical example is the widespread

Therefore, strategies for achieving cultural appropriateness should match the nature of the problem being addressed. The World Health Organization's Sustainable Development Goal Number 10 which seeks to eliminate health disparities can only be achieved by programs which have been adapted based on cultural considerations. This way they will succeed where

Previous research abounds to prove that minority groups within populations are at a much higher risk of suffering from adverse health conditions such as cardiovascular disease, cancer, etc. While the epidemiology of these conditions indicates that several factors are at play, sociocultural factors have been found to exert a very strong influence on the occurrence of

to the outcome of interest, and have been **derived from an individual assessment.**

**5. Cultural targeting vs. cultural tailoring: striking a balance**

approach effective. In reality, this is not always the case.

and description is required for better outcomes [20].

while targeting becomes the more important approach.

belief in God in African societies.

other programs have failed.

**4.2. Cultural tailoring**

34 Current Issues in Global Health

As the abovementioned evidence accumulated over the years, solutions in the form of "cultural competence" in health care have been prescribed. This refers to a situation where the importance of culture and cultural disparities is taken into consideration and where the design of health programs and services addresses the peculiar cultural needs of a target population. As a result, understanding and addressing the "social context" has emerged as a critical component of cultural competence [26].

A culturally competent healthcare agency, program, or individual provider can function effectively and appropriately in healthcare delivery to culturally diverse individuals. It also involves understanding, appreciation, and respect for cultural differences and similarities within, among, and between culturally diverse populations. To be culturally competent in healthcare delivery, the health professional needs to be sensitive to the differences between groups, to the differences in outward behavior, and also to the attitudes and meanings attached to emotionally related health issues like depression, pain, and disability [29].

The extent to which a society perceives health information or medication as being relevant to them has a profound effect on their reception to and willingness to use them. Even at individual levels, culture-specific values greatly influence perception of sickness and disease, patient roles, expectations, how much information the patient desires, what treatment modalities are acceptable, gender and family roles, and processes of taking decisions concerning health care [26].

It is important to note that no two patients will interpret what good health care is in exactly the same way. This interpretation will be based on personal backgrounds and experiences which have been found to be influenced to a large extent by factors like age, gender, ethnicity, race, religion, and economic status. These factors influence the perception of the individual who receives a health service or product [30]. Therefore, it is important to note that a culturally sensitive healthcare delivery system limits barriers as regards culture and language thus bringing about desirable health outcomes and positive behavioral adjustments.

neighbors or coworkers discovered his secret, he would become a laughing stock of the community. He would lose his respect, people would keep their distance from him, even avoid

Cultural Sensitivities and Health

37

http://dx.doi.org/10.5772/intechopen.79455

He had been referred to an HIV clinic at the big hospital at the center of town. He was not comfortable going there. He would have preferred a place at the outskirts of town or even another town where he was unknown. He cautiously approached the entrance to the clinic which he identified with the large signboard outside it. As he made to enter, he saw his landlord Chief Alfred Nwosu stepping out of the clinic with a polythene bag in his hand, glancing cautiously in either direction as he made to exit the clinic. Audu swiftly changed his direction and hurried away before he was spotted. He walked back to the car park and drove his car

What went wrong? The clinic was located separately from other clinics in the hospital making it easy to identify its clients. In African countries like Nigeria, HIV is still associated with a lot of prejudice against the victim as most people associate it with sexual promiscuity, even blaming patients for their condition. Audu would rather take his chances elsewhere than be

Dr. Sanjay Patel sat down in his consulting room at the large hospital in Calgary, Alberta, where he worked as an Obs/Gyn consultant providing family planning services. His last client for the day was a middle-aged woman of Asian descent. Her file indicated she was 42 years old and that her name was Mrs. Fei hung Zhao. It also indicated a bad obstetric history and the fact that she already had five children. Three minutes into the interaction, it dawned on Dr. Patel that his client's understanding of English was quite poor. Further enquiry revealed that there was no member of staff who could speak any Chinese. He tried to get across to her with some basic words and a lot of sign language. She refused the hormonal contraception (as an injection or IUCD) which was ideal for women of her age but preferred oral pills. He tried his best to instruct her on how to take them and asked her to return in a month with a family

What went wrong? The Mandarin community comprises about 3% of the Canadian population. It is a conservative society and as such Fei hung was not comfortable discussing birth control with a man, especially one of a different race. Not one member of the Chinese community worked in the hospital. The language barrier ensured that she did not understand most of Dr. Patel's attempt to educate her and her rejection of hormonal contraception was because she felt it would make her fat. She misunderstood the directions on how to take her pills and when to return. By the time she got pregnant, she was shocked and disappointed; she really

When there is a failure to properly appreciate, understand, and even explore cultural differences during the patient-provider interaction, clinical barriers to healthcare delivery arise.

member. Fei hung returned 5 months later; she was 3 months pregnant.

him completely.

away hurriedly. He never came back.

felt she had done all the right things.

**7.4. Clinical level**

seen at the clinic, than to be labeled one of "them."

**7.3. Case study 2 (a transgression of the principle)**

Cultural competency is one of the main ingredients in closing existing disparities in access to health care. It is one-way healthcare providers, and their target audiences can always find a common ground as they address health issues. Patients and doctors, population groups, and healthcare organizations can work together to achieve positive health outcomes in such a way that cultural differences become an advantage instead of a weakness. This is possible when the beliefs, practices, and cultural needs of communities are given high priority [31].

Agreement on what terms to use is not universal as words like "cultural responsiveness," "cultural humility," and cultural effectiveness" have been used, each of which has a unique definition. However, a sense of agreement exists based on the fact that each proponent of the above terms has recognized certain aspects of health delivery, especially the patient-provider relationship, as critical part of the concept. What seems to be lacking, however, is the development of a more comprehensive approach to thinking about and implementing cultural competence in health care at multiple levels and from multiple perspectives in order to overcome barriers which exist at organizational and individual levels.


Meet the editor

Prof. Dr. Mohamed Samer is a laureate of the 2019 Cairo University Scientific Excellence Award. He is also the recipient of the 2017 Privilege Medal of First Class issued by the Egyptian President and laureate of the 2016 State Encouragement Award conferred by the Egyptian Government. He obtained his Ph.D. from the University of Hohenheim, Germany. He has led seventeen research projects and established five research lab-

oratories. Dr. Samer has 120 publications, 70 of which are peer-reviewed articles published in high-impact journals, and 20 patents to his credit. He is a member of thirteen scientific societies and a peer reviewer for thirty scientific journals. He is also a reviewer for seven research funding agencies.


**Author details**

corrosion resistance of the coatings (30 mV potential shift). Ref. [70] reported MoS2 particles to lower friction the coefficient of Ni–W matrix and enhance its tribological properties.

Electroplated nickel composite/nanocomposite coatings find applications in machining and finishing of tools requiring excellent corrosion and wear resistance, low friction, and high thermal stability. Wear, friction, and corrosion pose a serious threat to machine lifespan, energy consumption, and performance. These phenomena also compromise the safety of the person‐ nel where the machine is used. Therefore, engineers prefer machines that have long lifespan, save energy, and have better performance throughout its service life. These machines or tools are made of lighter and cost-effective materials such as aluminium and steel, to enhance their quality; materials harder and chemically stable than them are used as coatings to protect them from surface degradation. Nickel, nickel alloy, and composite/nanocomposite coatings are

Ni–SiC nanocomposite coatings are used to offer wear protection of aluminium-made engine pistons in automotive industry [70]. These parts operate under high temperatures and wear conditions. Other candidates that perform similar function of lining of cylinders in aluminium

Electrodeposited Ni/diamond coatings have found applications in grinding and cutting tools, such as precision cutting wheels for dicing semiconducting silicon plates [71]. These also include nickel alloy composite coatings such as Ni–W reinforced with diamond nanoparticles. These coatings exhibit high hardness, excellent wear resistance, and elevated thermal stability.

Ni–PTFE composite coatings find use in precise mechanical parts [17]. These possess selflubricating properties and are convenient for applications that require low friction. Other suitable coatings to perform similar functions are Ni–CNT, MoS2, graphite, Si3N4, Ni–B, and

This chapter outlines the fabrication of nickel composite/nanocomposite coatings, their properties, and applications. Due to the excellent properties exhibited by these coatings such as high hardness, excellent corrosion resistance and wear resistance, self-lubricating proper‐ ties, and high thermal stability, the coatings have a good potential to replace chromium-based coatings. Their mechanism of co-deposition and optimization of process parameters need to be understand well to produce better coatings with improved surface properties. This understanding will also enable extension of their applications in the future to serve as

alternatives for other coatings fabricated by cost and energy-intensive processes.

perfect candidates for improving the quality of these materials.

BN composite coatings. They also exhibit high oxidation resistance.

engines are Ni–Al2O3, TiO2, WC, Cr2O3, etc. [71].

**7. Applications**

224 Electrodeposition of Composite Materials

**8. Conclusion**

Nicholus Malatji and Patricia A.I. Popoola\*

\*Address all correspondence to<EMAIL_ADDRESS>
Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria, South Africa