Pressure driven phase transitions in the magnetically frustrated layered material, Ca2Mn3O8

Frustration occurs in materials where antiferromagnetic (spin up and spin down pairs) are incomparible with the underlying crystal morphology, for example where the connectivity between magnetic ions has a triangular motif. In these magnetic materials the magnetically ordered state is often unconventional. Calcium manganese oxide, Ca2Mn3O8, exhibits managnese oxide layers seperated by calcium ions. Within the layers a complex "bow-tie" like connectivity of the maganese leads to a "two up two down" spin arrangement below a temperature of approximately 50 K. We would like to conduct new experiments as a function of applied pressure and temperature to extend these initial studies. This will allow us to correlate applied pressure with chemical pressure to target new frustrated materials.

阻挫（frustration）现象出现于反铁磁（antiferromagnetic）相互作用（自旋向上与自旋向下配对）与本征晶体形貌（crystal morphology）不相容的材料体系中，例如磁离子（magnetic ions）间的连接构型具有三角基元（triangular motif）的体系。此类磁材料的磁有序态（magnetically ordered state）通常呈现非寻常特性。钙锰氧化物（Calcium manganese oxide）Ca₂Mn₃O₈具有由钙离子分隔的氧化锰层（manganese oxide layers）；层内锰离子的"蝴蝶结状"连接构型（bow-tie like connectivity）会在约50开尔文以下的温度区间形成"两上两下"的自旋排布（spin arrangement）。本研究拟开展以外加压力（applied pressure）与温度为调控变量的全新实验，以拓展上述初步研究工作。该实验将实现外加压力与化学压力（chemical pressure）的关联分析，从而靶向开发新型阻挫材料（frustrated materials）。