Magnetically induced metal-insulator transition in Pb2CaOsO6

DOI: 10.1103/PhysRevB.102.214409

Authors: Henrik Jacobsen (University of Oxford; Paul Scherrer Institute) , Hai L. Feng (National Institute for Materials Science; Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences) , Andrew J. Princep (University of Oxford; ISIS Pulsed Neutron and Muon Source) , Marein C. Rahn (University of Oxford) , Yanfeng Guo (ShanghaiTech University) , Jie Chen (National Institute for Materials Science, Japan) , Yoshitaka Matsushita (National Institute for Materials Science, Japan) , Yoshihiro Tsujimoto (National Institute for Materials Science, Japan) , Masahiro Nagao (Nagoya University) , Dmitry Khalyavin (ISIS Pulsed Neutron and Muon Source) , Pascal Manuel (ISIS Pulsed Neutron and Muon Source) , Claire A. Murray (Diamond Light Source) , Christian Donnerer (University College London) , James G. Vale (University College London) , Marco Moretti Sala (European Synchrotron Radiation Facility) , Kazunari Yamaura (National Institute for Materials Science, Japan) , Andrew T. Boothroyd (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 102

State: Published (Approved)
Published: December 2020
Diamond Proposal Number(s): 9839

Abstract: We report on the structural, magnetic, and electronic properties of two new double-perovskites synthesized under high pressure, Pb 2 CaOsO 6 and Pb 2 ZnOsO 6 . Upon cooling below 80 K, Pb 2 CaOsO 6 simultaneously undergoes a metal-to-insulator transition and develops antiferromagnetic order. Pb 2 ZnOsO 6 , on the other hand, remains a paramagnetic metal down to 2 K. The key difference between the two compounds lies in their crystal structures. The Os atoms in Pb 2 ZnOsO 6 are arranged on an approximately face-centered 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 Pb 2 CaOsO 6 is heavily distorted up to at least 500 K including antiferroelectriclike 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 Pb 2 CaOsO 6 is spin driven and could be a rare example of a Slater transition.

Journal Keywords: Antiferroelectricity; Antiferromagnetism; Crystal structure; Magnetic phase transitions; Metal-insulator transition

Subject Areas: Materials, Physics


Instruments: I11-High Resolution Powder Diffraction

Other Facilities: ID20 at ESRF; ISIS