Butterfly-shaped magnetoresistance in triangular-lattice antiferromagnet Ag2CrO2

Hiroki Taniguchi; Mori Watanabe; Masashi Tokuda; Shota Suzuki; Eria Imada; Takashi Ibe; Tomonori Arakawa; Hiroyuki Yoshida; Hiroaki Ishizuka; Kensuke Kobayashi; Yasuhiro Niimi

doi:10.1038/s41598-020-59578-z

Butterfly-shaped magnetoresistance in triangular-lattice antiferromagnet Ag₂CrO₂

Sci Rep. 2020 Feb 13;10(1):2525. doi: 10.1038/s41598-020-59578-z.

Authors

Hiroki Taniguchi¹, Mori Watanabe¹, Masashi Tokuda¹, Shota Suzuki¹, Eria Imada¹, Takashi Ibe¹, Tomonori Arakawa^{1

2}, Hiroyuki Yoshida³, Hiroaki Ishizuka⁴, Kensuke Kobayashi^{1

5

6}, Yasuhiro Niimi^{7

8}

Affiliations

¹ Department of Physics, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan.
² Center for Spin Research Network, Osaka University, Toyonaka, 560-8531, Japan.
³ Department of Physics, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan.
⁴ Department of Applied Physics, Graduate School of Engineering, The University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan.
⁵ Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
⁶ Institute for Physics of Intelligence, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
⁷ Department of Physics, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan. niimi@phys.sci.osaka-u.ac.jp.
⁸ Center for Spin Research Network, Osaka University, Toyonaka, 560-8531, Japan. niimi@phys.sci.osaka-u.ac.jp.

Abstract

Spintronic devices using antiferromagnets (AFMs) are promising candidates for future applications. Recently, many interesting physical properties have been reported with AFM-based devices. Here we report a butterfly-shaped magnetoresistance (MR) in a micrometer-sized triangular-lattice antiferromagnet Ag₂CrO₂. The material consists of two-dimensional triangular-lattice CrO₂ layers with antiferromagnetically coupled S = 3/2 spins and Ag₂ layers with high electrical conductivity. The butterfly-shaped MR appears only when the magnetic field is applied perpendicularly to the CrO₂ plane with the maximum MR ratio (≈15%) at the magnetic ordering temperature. These features are distinct from those observed in conventional magnetic materials. We propose a theoretical model where fluctuations of partially disordered spins with the Ising anisotropy play an essential role in the butterfly-shaped MR in Ag₂CrO₂.