Doping of Multiferroic Bulk and Nanosized Objects. Numerilac calculations and discussion (part ii) Doping of Multiferroic Bulk and Nanosized Objects. Numerilac calculations and discussion (part ii)

Based on the developed model in Part I of this study [1], the multiferroic characteristics of doped compounds with transition metals and rare earth elements have been numerically calculated. The obtained results are in good agreement with the experimental investigations. The influence of impurities, sizes, and shapes is accounted for by altering the interaction constants within each subsystem and between them. In examining the effects of doping, we employ the so-called coherent potential approximation, working within concentration intervals of impurities that do not exceed the solubility limit for solid solutions. To address size effects, we use model multiferroic spherical nanoparticles that are compositionally homogeneous but structurally heterogeneous. These nanoparticles have a core with microscopic parameters similar to bulk samples and a shell (surface) with altered parameters and interactions. A methodology for determining the necessary interaction constants for numerical calculations has been established. The obtained results are analyzed and explained from a physical standpoint, taking into account the microscopic features of the system.