Dielectric and Mossbauer Studies of Perovskite Multiferroics

Abstract

Mossbauer spectra studies were used to determine the temperatures of magnetic phase transitions in some Fe-containing perovskite multiferroics and their solid solutions. In compositionally disordered materials the temperature T_N of antiferromagnetic phase transition depends linearly on Fe³⁺ content. Partial ordering of Fe³⁺ and B⁵⁺ cations in Pb(Fe_1/2B_1/2)O₃ (B = Nb, Ta) ternary perovskites decreases T_N by more than 50 K. At the same time the temperature T _m of dielectric permittivity maximum remains unchanged for Pb(Fe_1/2Nb_1/2)O₃ and increases for Pb(Fe_1/2Ta_1/2)O₃. These results are in line with existing theoretical models of B-cation ordering effect on T_N and T _m values in PbB³⁺ _1/2B⁵⁺ _1/2O₃ perovskites.

Keywords:

• compositional ordering
• dielectric permittivity
• Mössbauer spectra
• multiferroics

Acknowledgments

This study is partially supported by RFBR (grants 05-03-32214 and 08-02-92006 NNS) and Taiwan National Science Council in the frame of NSC-RFBR 2005–2006 Joint Research Project 94WFD0100021.