第31回フロンティア材料研究所講演会 (Professor Youwen Long)

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第31回フロンティア材料研究所講演会

講師： Professor Youwen Long
　　　　(Institute of Physics, Chinese Academy of Science)

講演テーマ： "High pressure synthesis and physical properties of new perovskite oxides"

 Abstract:
Co-based oxides show fascinating physical properties such as colossal magnetoresistance, unconventional superconductivity, large linear magnetoelectric effect, and high-performance thermoelectricity etc. Different from other 3d transition metals, the family member of ACoO₃ perovskite is very limited. By using high-pressure and high-temperature synthesis methods, we obtained two new Co-based perovskites CaCoO₃ and PbCoO₃. The metallic CaCoO₃ has a pseudo-cubic crystal structure and shows two magnetic phase transitions (one FM and another AFM). The insulating PbCoO₃ shows unusual A- and B-site charge orders. High pressure may induce charge transfer in PbCoO₃ based on our primary pressure dependent measurements. In addition to these two simple ABO₃ perovskites, we also prepared A-site ordered perovskites La/BiMn₃Cr₄O₁₂ with Im-3 cubic space group. Magnetoelectric multiferroicity with large electric polarization and strong magnetoelectric coupling was found. This is the first observation of multiferroicity in cubic perovskite systems.