Pressure-induced structural change in orthorhombic perovskite GdMnO3
Pressure-induced structural change in orthorhombic perovskite GdMnO3
复制标题
压力引起的斜方钙钛矿 GdMnO3 的结构变化
DOI：
10.1088/0953-8984/24/11/115402
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发表时间：
2012-03-21
影响因子：
2.7
通讯作者：
Xiong, Lun
中科院分区：
文献类型：
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作者：
Lin, Chuanlong;Zhang, Yufeng;Xiong, Lun
用同步辐射角色散X射线衍射技术研究了钙钛矿型GdMnO_3的结构稳定性。GdMnO 3保持正交晶系结构，但在50 GPa下经历了体积减小约5%的同构相变。在母相正交相中，沿沿着a、B和c轴的压缩表现出较大的各向异性。结果表明，随着压力的增加，MnO_6八面体的畸变和倾斜度不断减小，正交结构向更高的对称性演化。用三阶Birch-Murnaghan状态方程对实验数据进行拟合，得到正交相起始相的体积模量B 0 = 156（3）GPa，B 0 ′ = 6.5（3）。在减压时，恢复起始斜方晶相。
Structural stability of the perovskite-type GdMnO3 has been investigated by the synchrotron angle-dispersive x-ray diffraction technique up to 63 GPa in a diamond anvil cell. GdMnO3 stays in an orthorhombic structure but undergoes an isostructural phase transition with ∼5% volume reduction at 50 GPa. In the parent orthorhombic phase, the compressions along a, b and c axes exhibit a large anisotropic behavior. With increasing pressure, our results show that the distortion and tilts of the MnO6 octahedra are reduced continuously and the orthorhombic structure evolves towards higher symmetry. By fitting the observed pressure–volume data using the third-order Birch–Murnaghan equation of state, we obtain the bulk modulus B0 = 156(3) GPa with B0′ = 6.5(3) for the starting orthorhombic phase. Upon decompression, the starting orthorhombic phase is recovered.