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arXiv 2009.04196cond-mat.str-el
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Pb2CaOsO6的磁致金属-绝缘体相变

Magnetically induced metal-insulator transition in Pb2CaOsO6

Henrik Jacobsen, Hai L. Feng, Andrew J. Princep, Marein C. Rahn, Yanfeng Guo, Jie Chen, Yoshitaka Matsushita, Yoshihiro Tsujimoto, Masahiro Nagao, Dmitry Khalya… 展开作者

Henrik Jacobsen, Hai L. Feng, Andrew J. Princep, Marein C. Rahn, Yanfeng Guo, Jie Chen, Yoshitaka Matsushita, Yoshihiro Tsujimoto, Masahiro Nagao, Dmitry Khalyavin, Pascal Manuel, Claire A. Murray, Christian Donnerer, James G. Vale, Marco Moretti Sala, Kazunari Yamaura, Andrew T. Boothroyd

摘要:

我们报告的结构,磁性和电子性能的两个新的双钙钛矿高压下合成; Pb 2CaOsO 6和Pb 2 ZnOsO 6。当冷却到80 K以下时,Pb 2CaOsO 6同时经历金属-绝缘体转变并发展反铁磁有序。另一方面,Pb 2 ZnOsO 6在低至2K时仍然是顺磁性金属。这两种化合物的主要区别在于它们的晶体结构。Pb 2 ZnOsO 6中的Os原子排列在近似面心立方晶格上,具有强的反铁磁最近邻交换耦合。这种晶格固有的几何挫折阻止了磁序的形成,直到最低温度。相比之下,Pb 2CaOsO 6的晶胞在至少500 K时严重扭曲,包括Pb和O原子的反铁电性位移,尽管金属导电性高于80 K。这种扭曲减轻了磁挫折,促进了磁秩序,这反过来又驱动了金属-绝缘体转变。我们的研究结果表明,相变在Pb 2CaOsO 6是自旋驱动的,可能是一个罕见的斯莱特转变的例子。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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