Pressure-Induced Spin-State Transition in BiCoO3

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• 作者：Kengo Oka ; Masaki Azuma ; Wei-tin Chen ; Hitoshi Yusa ; Alexei A. Belik ; Eiji Takayama-Muromachi ; Masaichiro Mizumaki ; Naoki Ishimatsu ; Nozomu Hiraoka ; Masahiko Tsujimoto ; Matthew G. Tucker ; J. Paul Attf
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：July 14, 2010
• 年：2010
• 卷：132
• 期：27
• 页码：9438-9443
• 全文大小：293K
• 年卷期：v.132,no.27(July 14, 2010)
• ISSN：1520-5126

文摘

The structural and electronic properties of BiCoO₃ under high pressure have been investigated. Synchrotron X-ray and neutron powder diffraction studies show that the structure changes from a polar PbTiO₃ type to a centrosymmetric GdFeO₃ type above 3 GPa with a large volume decrease of 13% at room temperature revealing a spin-state change. The first-order transition is accompanied by a drop of electrical resistivity. Structural results show that Co³⁺ is present in the low spin state at high pressures, but X-ray emission spectra suggest that the intermediate spin state is present. The pressure−temperature phase diagram of BiCoO₃ has been constructed enabling the transition temperature at ambient pressure to be estimated as 800−900 K.