the absolute values of $m_y^1$ and $m_y^2$ are close but not identical at temperatures $T > 0$.

Figure 9 shows the different sublattice magnetizations for $J_{xz}= 16.2 J'$, $D = -8.1 J'$, and $H_x =0.75 H_z$, i.e. a field with axial and planar components is considered. At low temperatures, the antiferromagnetic ordering of the axial spin components and the spin–flop ordering of the planar spin components is clearly seen. When the system is heated, a drastic change in the y-component of the layer magnetization takes place at $T_{xy}$ well below $T_c$. For the chosen parameters, the change in the $y$–components is continuous. For values of $\left| J_{xz} \right|$ larger than the threshold value, e.g. $J_{xz}= 21.6 J'$, this change occurs through a jump in the layer magnetization leading to a first–order transition. At first it may be surprising that the $y$–components (and also the $x$–components) of the sublattice magnetization are not equal at temperatures above $T_{xy}$ and below $T_c$, see Figure 9. In fact, this is explained by the finite value of the axial field $H_z$ which tends to destabilize the $z$–components in the “$-$” layers, thus leading to different sublattice magnetizations in the different layer types. As a result 