July 2014, Volume 66, Issue 7, pp 1138–1143 | Cite as

Modeling of Nd-Oxide Grain Boundary Phases in Nd-Fe-B Sintered Magnets

We use atomistic and micromagnetic simulations combined with atomic-scale, aberration-corrected transmission electron microscopy to study the anisotropy profile of the interface between a Nd2O3-hP5 and a Nd2Fe14B phase. It is shown that a hybrid Morse-Buckingham potential approach can be used to study mixed-metallic and oxide-rich systems and to calculate surface-energy-induced large strains and potentially large relaxation effects on the adjacent grains. These are used to derive a magnetoelastic anisotropy energy from a first-order perturbation of the magnetoelastic Hamiltonian and are used to evaluate its effect on coercivity. It is shown that the change in coercivity originates from these distortions in the Nd2Fe14B crystal lattice close to the grain boundary, and the coercivity can be evaluated using such a multiscale modeling approach.

Nd2O3 Magnetocrystalline Anisotropy Lattice Minimization Energy Minimum State Sintered Magnet

The authors gratefully acknowledge financial support from the Toyota Motor Corporation and the fruitful discussions with Dr. Kato, Dr. Tetsuja, and Dr. Yano and the EPSRC for financial support under Grants EP/G032440/1 and EP/G032300/1, the WWTF Project MA09-029, and the Royal Society.

© The Minerals, Metals & Materials Society 2014

Hrkac, G., Butler, K., Woodcock, T.G. et al. JOM (2014) 66: 1138. https://doi.org/10.1007/s11837-014-0980-5
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