Phase variation of ferroelectric Li2Sr1-xCax(Nb1-xTax)2O7 by selective reinforcement in the (Nb,Ta)-O covalent bonds
Phase variation of ferroelectric Li2Sr1-xCax(Nb1-xTax)2O7 by selective reinforcement in the (Nb,Ta)-O covalent bonds
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(Nb,Ta)-O 共价键选择性强化导致铁电 Li2Sr1-xCax(Nb1-xTax)2O7 的相变
DOI：
10.1103/physrevmaterials.6.044412
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发表时间：
2022
影响因子：
3.4
通讯作者：
Taniguchi Hiroki
中科院分区：
文献类型：
--
作者：
Nakano Akitoshi;Shirakuni Hirokazu;Nagai Takayuki;Mochizuki Yasuhide;Oba Fumiyasu;Yokota Hiroko;Kawaguchi Shogo;Terasaki Ichiro;Taniguchi Hiroki
利用介电测量、二次谐波产生和X射线衍射实验系统地研究了赝Roddlesden-Popper型铁电氧化物的相变。我们发现了一个奇异的T相图，包括顺电Cmcm，反铁电Pmcn，以及面内反铁电和面外铁电相。在低，我们观察到大的和发散的介电异常与相变从Cmcm到，而这些成为小扭结在高。结构分析揭示了一个内部的扭曲，和旋转的八面体强烈依赖，这是一致的晶格动力学通过密度泛函理论计算。这些结果表明，通过调整八面体中的化学键合状态，层状钙钛矿型氧化物的介电性能具有很大的可调性。
A phase variation of a pseudo-Roddlesden-Popper-type ferroelectric oxideis systematically investigated using dielectric measurements, second harmonic generation, and x-ray diffraction experiments. We find an exotic-Tphase diagram, including paraelectricCmcm, antiferroelectricPmcn, and in-plane antiferroelectric and out-of-plane ferroelectricphases. At low, we observe large and divergent dielectric anomalies associated with phase transitions fromCmcmto, whereas these become small kinks at high. Structural analyses reveal an internal distortion, and the rotation of octahedra strongly depends on, which is consistent with the lattice dynamics obtained by a density functional theory calculation. These results demonstrate the great tunability of dielectric properties in layered perovskite-type oxides by tuning the chemical bonding state in the octahedron.