Mallick Subhadip, Orlandi Fabio, Manuel Pascal, Zhang Weiguo, Halasyamani P Shiv, Hayward Michael A
Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, UK.
ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, UK.
Chem Mater. 2023 Sep 9;35(18):7839-7846. doi: 10.1021/acs.chemmater.3c01850. eCollection 2023 Sep 26.
Reaction between the pseudo-Ruddlesden-Popper phase LiCaTaO and MnCl at 375 °C yields MnCaTaO, a paramagnetic polar phase (space group 2), which adopts an / distorted, layered perovskite structure. Magnetization and neutron diffraction data show that MnCaTaO adopts an antiferromagnetically ordered state below = 56 K and exhibits large lattice parameter anomalies and a transient increase in its polar distortion mode at = 50 K. However, in contrast to the related phase MnSrTaO, MnCaTaO shows no strong signature of weak ferromagnetism and thus shows no signs of magnetoelectric coupling. The differences in physical behavior between the two MnTaO phases appear to be related to their differing Mn cation-order and differing TaO tilting schemes and demonstrate that even subtle changes to these orderings can have large effects on the distortion-mode couplings, which drive complex behavior of this class of "hybrid improper" ferroelectric material.
在375°C下，准Ruddlesden-Popper相LiCaTaO与MnCl反应生成MnCaTaO，这是一种顺磁极性相（空间群2），其采用/扭曲的层状钙钛矿结构。磁化和中子衍射数据表明，MnCaTaO在低于 = 56 K时采用反铁磁有序状态，并在 = 50 K时表现出大的晶格参数异常及其极性畸变模式的瞬态增加。然而，与相关相MnSrTaO相比，MnCaTaO没有显示出弱铁磁性的强烈特征，因此也没有磁电耦合的迹象。两种MnTaO相之间物理行为的差异似乎与其不同的Mn阳离子有序和不同的TaO倾斜方案有关，并表明即使这些有序的细微变化也会对畸变模式耦合产生很大影响，从而驱动这类“混合非本征”铁电材料的复杂行为。
