Pressure-induced spin-state transition in BiCoO3.
The structural and electronic properties of BiCoO(3) under high pressure have been investigated. Synchrotron X-ray and neutron powder diffraction studies show that the structure changes from a polar PbTiO(3) type to a centrosymmetric GdFeO(3) 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 Co(3+) 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 BiCoO(3) has been constructed enabling the transition temperature at ambient pressure to be estimated as 800-900 K.
Oka
Kengo
K
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan. oka@issp.u-tokyo.ac.jp
Azuma
Masaki
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Chen
Wei-tin
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Yusa
Hitoshi
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Belik
Alexei A
AA
Takayama-Muromachi
Eiji
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Mizumaki
Masaichiro
M
Ishimatsu
Naoki
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Hiraoka
Nozomu
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Tsujimoto
Masahiko
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Tucker
Matthew G
MG
Attfield
J Paul
JP
Shimakawa
Yuichi
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