Towards novel multiferroic and magnetoelectric materials: dipole stability in tetragonal tungsten bronzes
Towards novel multiferroic and magnetoelectric materials: dipole stability in tetragonal tungsten bronzes
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DOI：
10.1098/rsta.2012.0451
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发表时间：
2014-02
期刊：
影响因子：
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通讯作者：
A. Rotaru;Andrew J. Miller;D. Arnold;F. Morrison
中科院分区：
文献类型：
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作者：
A. Rotaru;Andrew J. Miller;D. Arnold;F. Morrison
讨论了四钨青铜结构新型功能材料的发展策略。从起始组合物Ba 6 GaNb 9 O30，A-和B-位点取代的介电性能的影响是用来开发的起源和稳定性的理解，在这些化合物中的偶极响应。两个tetraphylococcus应变引起的大B-网站的阳离子和本地应变的变化所创建的等价的A-网站取代增强偶极稳定性，但在稀释，弱相关的偶极响应和典型的弛豫行为的结果。降低钙钛矿A2-位点处的阳离子尺寸增加周围八面体中的偶极位移，但不足以导致偶极有序。介绍了引入小的A位镧系阳离子和掺入A位空位诱导铁电性和磁性的机制。
We discuss the strategy for development of novel functional materials with the tetragonal tungsten bronze structure. From the starting composition Ba6GaNb9O30, the effect of A- and B-site substitutions on the dielectric properties is used to develop an understanding of the origin and stability of the dipolar response in these compounds. Both tetragonal strain induced by large B-site cations and local strain variations created by isovalent A-site substitutions enhance dipole stability but result in a dilute, weakly correlated dipolar response and canonical relaxor behaviour. Decreasing cation size at the perovskite A2-site increases the dipolar displacements in the surrounding octahedra, but insufficiently to result in dipole ordering. Mechanisms introducing small A-site lanthanide cations and incorporation of A-site vacancies to induce ferroelectricity and magnetism are presented.