Arnold Donna C, Knight Kevin S, Morrison Finlay D, Lightfoot Philip
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9ST, United Kingdom.
Phys Rev Lett. 2009 Jan 16;102(2):027602. doi: 10.1103/PhysRevLett.102.027602.
A detailed investigation using variable temperature powder neutron diffraction demonstrates that BiFeO3 undergoes a phase transition from the ferroelectric alpha phase (rhombohedral, R3c) to a paraelectric beta phase (orthorhombic, Pbnm) between 820 degrees C and 830 degrees C. Coexistence of both phases over a finite temperature interval, together with abrupt changes in key structural parameters, confirms that the transition is first order. The beta phase corresponds to a GdFeO3-type perovskite structure.
使用可变温度粉末中子衍射进行的详细研究表明，BiFeO₃在820℃至830℃之间经历了从铁电α相（菱面体，R3c）到顺电β相（正交，Pbnm）的相变。在有限温度区间内两个相的共存，以及关键结构参数的突然变化，证实了该转变是一级相变。β相对应于一种GdFeO₃型钙钛矿结构。
