Predicted model of magnetocaloric effect in BiFeO3-based multiferroics

摘要

Structure, magnetic properties and magnetocaloric effect in synthesized Bi-based multiferroics with a partial isovalent substitution of bismuth (III) cations for rare-earth elements (R = La, Nd, Sm, Eu, Gd, Dy, Er) have been studied. The samples have been prepared by the solid-state reaction method under cold pressing at high pressure (4 GPa). Proposed, for the first time, has been a modified phenomenological model for describing temperature dependences of magnetization and investigating a magnetocaloric effect within "weak ferromagnetic-antiferromagnetic" and "antiferromagnetic-paramagnetic" magnetic phase transition regions. Systematic changes of thermodynamic characteristics have been found out to depend on the degree of replacement and the type of a substituted cation.