Journal of Rare Earths ( IF 4.9 ) Pub Date : 2021-06-01 , DOI: 10.1016/j.jre.2021.05.010 Jiajun Ma , Qi Xu , Le Ye , Qinwen Wang , Zhixin Gong , Chao Shi , Hengyun Ye , Yi Zhang
In recent years, it has been found that the flexibility of structure and diversity of the components endow quite an amount of the organic-inorganic hybrid perovskites with novel properties, i.e., structural phase transitions. Considering the natural advantage of the perovskite-type structure in generation of stimuli-responsive or smart materials, we synthesized an organic-inorganic hybrid rare-earth double perovskite-type compound, (DMP)2LaRb(NO3)6 (DMP = N,N-dimethylpyrrolidinium cation, 1). It shows reversible phase transition at 219/209 K (heating/cooling). Variable-temperature single-crystal structure analysis and dielectric constant measurements reveal that the thermal vibrations of the polar cation guests and the distortion of the anionic cage-like framework are the origin of the phase transition. Meanwhile, the movement of polar cation in crystal lattices arouses dielectric transition between the low- and high-dielectric states, resulting in a switchable property of dielectric constant. The results reveal that the rare-earth double perovskite provides a promising platform for achieving switchable physical/chemical properties.
中文翻译:
有机-无机杂化稀土双钙钛矿型化合物的结构相变和介电转换:(DMP)2LaRb(NO3)6 (DMP = N,N-dimethylpyrrolidinium cation)
近年来,人们发现结构的灵活性和组分的多样性赋予了相当数量的有机-无机杂化钙钛矿以新颖的性质,即结构相变。考虑到钙钛矿型结构在生成刺激响应或智能材料方面的天然优势,我们合成了有机-无机杂化稀土双钙钛矿型化合物,(DMP) 2 LaRb(NO 3 ) 6 (DMP = N ,N-二甲基吡咯烷阳离子, 1)。它在 219/209 K(加热/冷却)下显示出可逆的相变。变温单晶结构分析和介电常数测量表明,极性阳离子客体的热振动和阴离子笼状骨架的变形是相变的起源。同时,极性阳离子在晶格中的运动引起了低介电态和高介电态之间的介电转变,导致介电常数的可切换特性。结果表明,稀土双钙钛矿为实现可转换的物理/化学性质提供了一个有前景的平台。