系统地总结了双钙钛矿氧化物的晶体结构特点,根据阳离子有序性的不同将双钙钛矿材料分为3类,即岩盐有序、柱状有序和层状有序,并分析了各类有序的形成条件;从B位含有非磁性阳离子的角度入手,介绍了锑基双钙钛矿氧化物的晶体结构特点及其易获得高度B位岩盐有序的机制,并以几种典型的锑基双钙钛矿氧化物为例讨论了该类氧化物的磁、电性质,特别是B位有序度等晶体结构的改变对该类氧化物物理性质的影响。最后介绍了关于A位为不同稀土离子、B位含锑双钙钛矿氧化物的最新研究工作,研究结果表明随着A位稀土离子的替换介电常数ε'值呈单调递减的趋势,说明镧系收缩抑制了过渡金属离子之间的3d电子的跃迁从而抑制极化畴的翻转;对于B位为不同过渡金属元素的化合物,介电常数ε'值按照磁矩减小的趋势呈单调递减规律,反映了磁性与介电性质之间存在着一定的耦合关系,这对更加深入地研究和探索双钙钛矿氧化物材料的磁电性质提供了有价值的参考信息。
The crystal structure characteristics of double perovskites were systematically summarized. According to the different arrangements of cations, the cationic ordering for perovskite materials could be divided into three types, i.e. rock-salt, columnar, and layered ordering. The conditions to form different cationic ordering types were also analyzed. To start with the non-magnetic cation at the B-site, the crystal structure and the mechanism of high degree rock-salt ordering at the B-sublattice for antimony-based double perovskites were elucidated. Taking several typical antimony-based double perovskites as an example, the magnetic and electric properties of these compounds were discussed, and particularly the influence of change of crystal structure such as the degree of B-site ordering on physical properties was discussed in detail. Finally, the present research works for double perovskites with different rare earth ions at A-site and antimony containing at the B-site were introduced. The results showed that the dielectric constants ε' decreased with the substitution of rare earth ions at the A-site, indicating that lanthanide contraction suppressed the 3d electron transfer between transition metal ions and the reversal of polar regions. The values of ε' decreased with the reduction of magnetic moments for different transition metal ions at the B-site, revealing a coupling relationship between magnetic and dielectric properties. Meanwhile, the beneficial information for investigating and exploring the magnetic and electric properties of double perovskite materials was also promoted.