Structural Properties of Multiferroic BiFeO3 under Hydrostatic Pressure

详细信息    查看全文

• 作者：Alexei A. Belik ; Hitoshi Yusa ; Naohisa Hirao ; Yasuo Ohishi ; Eiji Takayama-Muromachi
• 刊名：Chemistry of Materials
• 出版年：2009
• 出版时间：July 28, 2009
• 年：2009
• 卷：21
• 期：14
• 页码：3400-3405
• 全文大小：773K
• 年卷期：v.21,no.14(July 28, 2009)
• ISSN：1520-5002

文摘

High-pressure structural properties of multiferroic perovskite-type BiFeO₃ have been investigated by high-resolution synchrotron X-ray powder diffraction at room temperature up to 9.7 GPa. BiFeO₃ shows rather complicated structural behavior. The ambient-pressure ferroelectric R3c phase transforms to an orthorhombic phase OI at around 4 GPa during compression. The OI phase is characterized by a superstructure √2a_p × 3√2a_p × a_p, where a_p is the parameter of the cubic perovskite subcell (a = 5.4939(4) Å, b = 16.6896(9) Å, c = 3.8728(2) Å at 4.9 GPa). The OI phase transforms to an orthorhombic phase OII at around 7 GPa. The OII phase is characterized by a superstructure √2a_p × 3√2a_p × 2a_p (a = 5.5021(3) Å, b = 16.2439(11) Å, c = 7.6960(4) Å at 9.7 GPa). During decompression, significant hysteretic behavior was found. The OII phase was stable down to about 3 GPa. The OII phase then transforms to an orthorhombic phase OIII that is characterized by a superstructure √2a_p × 2√2a_p × 2a_p (a = 5.5617(6) Å, b = 11.2153(10) Å, c = 7.7788(7) Å at 2.2 GPa). The R3c phase appeared below about 1 GPa; however, even at ambient pressure, traces of the OIII phase remained. The OIII phase seems to be isostructural with antiferroelectric PbZrO₃ (space group Pbam).