Magnetic phase transitions in solid solutions of Fe-containing perovskite multiferroics

Concentration dependences of magnetic phase transitions temperatures T-M for several solid solutions of perovskite multiferroics BiFeO3, PbFe1/2Nb1/2O3 (PFN), and PbFe0.5Sb0.5O3 (PFS) have been studied using Mossbauer spectroscopy. In all the solid solutions studied, the values of T-M were found to depend not only on the concentration of the Fe3+ ions in the lattice, but also on the short-range and/or long-range ordering of Fe3+ and B5+ ions, as well as on the mean lattice parameter values and on the nontrivial magnetic superexchange involving the empty p-orbitals of Pb2+ and Bi3+ cations.