论文标题
PB2CAOSO6中的磁诱导金属胰蛋白过渡
Magnetically induced metal-insulator transition in Pb2CaOsO6
论文作者
论文摘要
我们报告了在高压下合成的两个新的双晶壶的结构，磁和电子特性； PB2CAOSO6和PB2ZNOSO6。冷却低于80 K时，PB2CAOSO6同时进行金属 - 绝缘体过渡并发展出抗铁磁顺序。另一方面，PB2ZNOSO6仍然是降低到2K的顺磁金属。两种化合物之间的关键差在其晶体结构。 PB2ZNOSO6中的OS原子在大约面对面的立方晶格上布置，并具有强烈的抗磁磁性最近的邻居交换耦合。该晶格固有的几何挫败感可防止磁性降低到最低温度。相比之下，尽管金属电导率高于80 K，但PB2CAOSO6的晶胞被严重扭曲至至少500 K，包括PB和O原子的抗固有样的位移。这种失真可缓解磁性挫败感，促进磁性磁性，从而促进了金属 - 旋转金属 - 启动金属 - 启动金属 - 启动金属 - 启动的磁性。我们的结果表明，PB2CAOSO6中的相变是自旋驱动的，这可能是Slater转变的罕见例子。
We report on the structural, magnetic, and electronic properties of two new double-perovskites synthesized under high pressure; Pb2CaOsO6 and Pb2ZnOsO6. Upon cooling below 80 K, Pb2CaOsO6 simultaneously undergoes a metal--insulator transition and develops antiferromagnetic order. Pb2ZnOsO6, on the other hand, remains a paramagnetic metal down to 2 K. The key difference between the two compounds lies in their crystal structure. The Os atoms in Pb2ZnOsO6 are arranged on an approximately face-centred cubic lattice with strong antiferromagnetic nearest-neighbor exchange couplings. The geometrical frustration inherent to this lattice prevents magnetic order from forming down to the lowest temperatures. In contrast, the unit cell of Pb2CaOsO6 is heavily distorted up to at least 500 K, including antiferroelectric-like displacements of the Pb and O atoms despite metallic conductivity above 80 K. This distortion relieves the magnetic frustration, facilitating magnetic order which in turn drives the metal--insulator transition. Our results suggest that the phase transition in Pb2CaOsO6 is spin-driven, and could be a rare example of a Slater transition.
