15:30-16:15

High-pressure synthesis and characterization of new multiferroic indium-based perovskites

Multiferroic materials combine both magnetic and electric dipole ordering. Multiferroics are quite interesting because they allow control of magnetic properties by electric field and vice versa. However, existing problems are (1) development of room-temperature (RT) multiferroics with (2) strong coupling between different order parameters. Strong coupling is realized in magnetically-induced ferroelectrics; however, transition temperatures are usually very low. Preparation of new materials having spontaneous polarization and magnetism at RT is very essential for the development of RT multiferroic materials.
Here, we describe a new class of multiferroic materials: In-based perovskites. We show that In_1-yM_yMO₃ with y = 0.112-0.176 and M = Fe_0.5Mn_0.5 is isostructural with BiFeO₃ and has a high ferroelectric Curie temperature; In_1-yM_yMO₃ is a canted antiferromagnet with the Neel temperature close to RT [1]. Our results give a significant contribution to the development of RT multiferroics and open wide possibilities for thin-film research and future improvement of In-based perovskites. Our results also show new ways for the preparation of perovskite-type materials. Perovskite, LiNbO3, corundum, and hexagonal modifications of In_1-yM_yMO₃ have been observed.

Results on (In_1-yMn_y)MnO₃ (1/9 ? y ? 1/3) [2], InCrO₃, and InFeO₃ will also be presented. It is proposed that the doping at the A-site occurs by Mn²⁺ ions, and (In_1-yMn_y)MnO₃ is similar with (Lu_1-yCa_y)MnO₃ and related materials. Ordering of Mn³⁺ and Mn⁴⁺ is suggested at the B sites. (In_1-yMn_y)MnO₃ (1/9 ? y ? 0.25) demonstrates spin-glass-like properties, and only (In2/3Mn1/3)MnO3 shows magnetic properties typical for canted antiferromagnets with T_N = 70 K. InCrO₃ has the GdFeO₃-type perovskite structure while InFeO₃ has a corundum-type structure.

[1] A.A. Belik, T. Furubayashi, Y. Matsushita, M. Tanaka, S. Hishita, E. Takayama-Muromachi, Angew. Chem. Int. Ed. 48, 6117, 2009. Highlighted in Nature Chemistry

[2] A.A. Belik, Y. Matsushita, M. Tanaka, E. Takayama-Muromachi, Angew. Chem. Int. Ed. 49, 7723, 2010.

Speaker

Dr. Alexei A. Belik, MANA Independent Scientist

Chair

Dr. Kazunari Yamaura, Senior Researcher, Superconducting Properties Unit, NIMS