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Recent interest in Bi-based perovskite oxides is motivated by intriguing predictions of multiferroic coupling in Bi-based oxide systems and by the possibility of replacing Pb-containing ferroelectrics with Bi analogues. The electronicconfiguration of the Bi³⁺ cation is similar to that of Pb²⁺ , and promotes polar structural distortions; while the flexibility of the trivalent M site in the A/M/O₃ perovskite structure allows for a wide range of transition metal cations chemistries that may promote magnetic and/or ferroelectric responses. In this talk I report on our recent work using high pressure, high temperature solid state methods to synthesize novel Bi-based perovskite oxide compounds. This high pressure synthetic approach provides access to many new meta-stable structures which cannot be realized under ambient pressure conditions. The focus of this work is primarily on systems of the general formula Bi(M`<sub>1/2</sub> M``<sub>1/2</sub>)O<sub>3</sub> , where M` and M`` are 2+, 3+, and 4+ transition metal cations. Several compounds with unanticipated structures have been identified in the course of this work; including the extremely tetragonally distorted Bi(Zn_1/2 Ti_1/2)O₃ and Bi(Co_1/2 V_1/2)O₃. The physical properties of these new compounds will be reported and discussed. Based on these new examples and previously known Bi-based perovskite compounds, connections can be made between the B site cation chemistry, the observed structural distortions, and the resulting physical properties in these systems.
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