Structural properties of PbVO3 perovskites under hydrostatic pressure conditions up to 10.6 GPa
Structural properties of PbVO3 perovskites under hydrostatic pressure conditions up to 10.6 GPa
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DOI：
10.1088/0953-8984/24/43/435403
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发表时间：
2012-10
期刊：
影响因子：
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通讯作者：
W. Zhou;D. Tan;W. Xiao;Maoshuang Song;Ming Chen;Xiaolin Xiong;Jian Xu
中科院分区：
文献类型：
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作者：
W. Zhou;D. Tan;W. Xiao;Maoshuang Song;Ming Chen;Xiaolin Xiong;Jian Xu
高压同步辐射X射线粉末衍射实验在金刚石对顶砧室中进行的PbVO 3四相钙钛矿在静水压力高达10.6 GPa，在室温下。PbVO 3四方相的压缩行为是高度各向异性的，c轴是软方向。在2.7和6.4 GPa之间的压缩和低于2.2 GPa的减压下，观察到可逆的四方晶系到立方钙钛矿结构相变。这种转变伴随着在2.7 GPa下10.6%的大体积塌陷，这主要是由于V4+离子的电子结构变化。V4+离子在四方相中的极性锥配位变为立方相中的各向同性八面体配位。用Birch-Murnaghan状态方程拟合了观测到的P-V数据，其中K 0 ′？>结果表明，四方相的体积模量K 0 = 61（2）GPa，体积模量V0 = 67.4（1）× 10 ~ 3，立方相的体积模量K 0 = 155（3）GPa，体积模量V0 = 58.67（4）× 10 ~ 3。第一性原理计算结果与实验结果符合较好。
High-pressure synchrotron x-ray powder diffraction experiments were performed on PbVO3 tetragonal perovskite in a diamond anvil cell under hydrostatic pressures of up to 10.6 GPa at room temperature. The compression behavior of the PbVO3 tetragonal phase is highly anisotropic, with the c-axis being the soft direction. A reversible tetragonal to cubic perovskite structural phase transition was observed between 2.7 and 6.4 GPa in compression and below 2.2 GPa in decompression. This transition was accompanied by a large volume collapse of 10.6% at 2.7 GPa, which was mainly due to electronic structural changes of the V4+ ion. The polar pyramidal coordination of the V4+ ion in the tetragonal phase changed to an isotropic octahedral coordination in the cubic phase. Fitting the observed P–V data using the Birch–Murnaghan equation of state with a fixed K 0 ′ ?> of 4 yielded a bulk modulus K0 = 61(2) GPa and a volume V0 = 67.4(1) Å3 for the tetragonal phase, and the values of K0 = 155(3) GPa and V0 = 58.67(4) Å3 for the cubic phase. The first-principles calculated results were in good agreement with our experiments.