Asymmetric ferromagnetic criticality in pyrochlore ferromagnet Lu2V2O7

Na Su; Feiye Li; Yuanyuan Jiao; Ziyi Liu; Jianping Sun; Bosen Wang; Yu Sui; Haidong Zhou; Gang Chen; Jinguang Cheng

doi:10.1016/j.scib.2019.06.025

Asymmetric ferromagnetic criticality in pyrochlore ferromagnet Lu₂V₂O₇

Sci Bull (Beijing). 2019 Sep 15;64(17):1222-1227. doi: 10.1016/j.scib.2019.06.025. Epub 2019 Jul 3.

Authors

Na Su¹, Feiye Li², Yuanyuan Jiao¹, Ziyi Liu³, Jianping Sun¹, Bosen Wang⁴, Yu Sui⁵, Haidong Zhou⁶, Gang Chen⁷, Jinguang Cheng⁸

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
² State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
³ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physics, Harbin Institute of Technology, Harbin 150001, China.
⁴ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China.
⁵ School of Physics, Harbin Institute of Technology, Harbin 150001, China.
⁶ Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA.
⁷ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Hong Kong, China. Electronic address: gangchen.physics@gmail.com.
⁸ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China. Electronic address: jgcheng@iphy.ac.cn.

PMID: 36659602
DOI: 10.1016/j.scib.2019.06.025

Abstract

We study the ferromagnetic criticality of the pyrochlore magnet Lu₂V₂O₇ at the ferromagnetic transition T_C≈70K from the isotherms of magnetization M(H) via an iteration process and the Kouvel-Fisher method. The critical exponents associated with the transition are determined: β = 0.32(1), γ = 1.41(1), and δ=5.38. The validity of these critical exponents is further verified by scaling all the M(H) data in the vicinity of T_C onto two universal curves in the plot of M/|ε|^β versus H/|ε|^β+γ, where ε=T/T_C-1. The obtained β and γ values show asymmetric behaviors on the T<T_C and the T>T_C sides, and are consistent with the predicted values of 3D Ising and cubic universality classes, respectively. This makes Lu₂V₂O₇ a rare example in which the critical behaviors associated with a ferromagnetic transition belong to different universality classes. We describe the observed criticality from the Ginzburg-Landau theory with the quartic cubic anisotropy that microscopically originates from the anti-symmetric Dzyaloshinskii-Moriya interaction as revealed by recent magnon thermal Hall effect and theoretical investigations.

Keywords: Critical behavior; Ferromagnetic transition; Ginzburg-Landau analysis; Lu(2)V(2)O(7) pyrochlore.