Our new paper “Thermally activated coercivity in core-shell permanent magnets” has been published today as J. Appl. Phys. 117, 17A733 (2015); http://dx.doi.org/10.1063/1.4916542 . In the paper we use numerical miromagnetics to calculate the performance of nanostructured core-shell-like permanent magnets, like the type that can now be produced by grain boundary diffusion of granular hot-deformed or sintered rare earth permanent magnets.
FIG. 3. Reversal processes in the sin- gle grain models with (i) a pure NdFeB grain, (ii) a NdFeB grain with a soft outer defect, and (iii) NdFeB core, (Dy, Nd)FeB shell and an outer soft defect. Thermally activated coercive field values are indicated with the field direction (red arrows). The saddle point image is the configuration with the highest total energy, forming the peak of the energy barrier.