Crystallographic features and tetragonal phase stability of PbVO3, a new member of PbTiO3 family
Crystallographic features and tetragonal phase stability of PbVO3, a new member of PbTiO3 family
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DOI：
10.1021/cm048387i
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发表时间：
2005-01-25
影响因子：
8.6
通讯作者：
Takano, M
中科院分区：
文献类型：
--
作者：
Belik, AA;Azuma, M;Takano, M
研究了常压和高压下PbVO3四方相的晶体学特征和稳定性，并与PbTiO3进行了比较，发现PbVO3与PbTiO3具有同型性[at 300 K，空间群P4mm； a = 3.803 91(5) 埃，c = 4.676 80(8) 埃，Z = 1]。 PbVO3 的四方性 (c/a) 是 PbTiO3 类化合物中最大的，并且随着温度从 12 K 升高到 570 K 而单调增加，而没有转变为立方相。大的四方性和从同步加速器X射线粉末衍射数据确定的原子位置表明存在超过100μC/cm(2)的大铁电极化。在空气中高于 570 K 时，PbVO3 被氧化成 Pb2V2O7。施加高压可防止氧化，因此在室温下从约 2 GPa 开始观察到伴随绝缘体到金属相变的四方到立方相变。
Crystallographic features and stability of the tetragonal phase of PbVO3 were investigated under ambient and high pressure and compared with those of PbTiO3, PbVO3 is isotypic with PbTiO3 [at 300 K, space group P4mm; a = 3.803 91(5) Angstrom and c = 4.676 80(8) Angstrom, Z = 1]. Tetragonality (c/a) of PbVO3 was the largest among the PbTiO3-type compounds and increased monotonically with increasing temperature from 12 to 570 K without transition to cubic phase. The large tetragonality and the atomic position determined from synchrotron X-ray powder diffraction data suggest a large ferroelectric polarization above 100 muC/cm(2). Above 570 K in air, PbVO3 was oxidized to Pb2V2O7. Application of high pressure prevented the oxidation and thus a tetragonal-to-cubic phase transition accompanied by an insulator-to-metal phase transition was observed from about 2 GPa at room temperature.