キュービックアンビルプレスを用いた機能性酸化物材料の合成 : サイト間電荷移動を示すBiNiO_3

概要

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High-pressure synthesis is a powerful technique in searching for new materials. We have found a large number of functional oxides using this technique. BiNiO3 is a distorted perovskite compound with unusual Bi1/23+Bi1/25+Ni2+O3 valence state. High-pressure neutron diffraction measurements and bond valence sum calculations show that the pressure-induced melting of the charge disproportionated state leads to a simultaneous charge transfer from Ni to Bi, so that the high-pressure phase is metallic Bi3+Ni3+O3. The same inter metallic charge transfer accompanied with 2.6% volume shrinkage is induced by heating Bi0.95La0.05NiO3 at ambient pressure.
2009-11-20