Tuning the Neel Temperature of Hexagonal Ferrites by Structural Distortion

Authors

Kishan Sinha, University of Nebraska - Lincoln
Haohan Wang, University of Nebraska - LincolnFollow
Xiao Wang, Bryn Mawr College
Liying Zhou, Temple University
Yuewei Yin, University of Nebraska - Lincoln
Wenbin Wang, Fudan University
Xuemei Cheng, Bryn Mawr College
David J. Keavney, Argonne National Laboratory
Huibo Cao, Oak Ridge National Laboratory
Yaohua Liu, Oak Ridge National Laboratory
Xifan Wu, Temple University
Xiaoshan Xu, University of Nebraska-LincolnFollow

Date of this Version

2018

Document Type

Article

Citation

PHYSICAL REVIEW LETTERS 121, 237203 (2018)

Comments

Used by permission.

Abstract

To tune the magnetic properties of hexagonal ferrites, a family of magnetoelectric multiferroic materials, by atomic-scale structural engineering, we studied the effect of structural distortion on the magnetic ordering temperature (T_N) in these materials. Using the symmetry analysis, we show that unlike most antiferromagnetic rare-earth transition-metal perovskites, a larger structural distortion leads to a higher T_N in hexagonal ferrites and manganites, because the K₃ structural distortion induces the three-dimensional magnetic ordering, which is forbidden in the undistorted structure by symmetry. We also revealed a nearlinear relation between T_N and the tolerance factor and a power-law relation between T_N and the K₃ distortion amplitude. Following the analysis, a record-high T_N (185 K) among hexagonal ferrites was predicted in hexagonal ScFeO₃ and experimentally verified in epitaxially stabilized films. These results add to the paradigm of spin-lattice coupling in antiferromagnetic oxides and suggests further tunability of hexagonal ferrites if more lattice distortion can be achieved.