Journal Article

Visualizing rotation and reversal of the Néel vector through antiferromagnetic trichroism

Kimura, Kenta, Otake, Yutaro, Kimura, Tsuyoshi

2022

Overview

Conventional magnetic memories rely on bistable magnetic states, such as the up and down magnetization states in ferromagnets. Increasing the number of stable magnetic states in each cell, preferably composed of antiferromagnets without stray fields, promises to achieve higher-capacity memories. Thus far, such multi-stable antiferromagnetic states have been extensively studied in conducting systems. Here, we report on a striking optical response in the magnetoelectric collinear antiferromagnet Bi 2 CuO 4 , which is an insulating version of the representative spintronic material, CuMnAs, with four stable Néel vector orientations. We find that, due to a magnetoelectric effect in a visible range, which is enhanced by a peculiar local environment of Cu ions, absorption coefficient takes three discrete values depending on an angle between the propagation vector of light and the Néel vector—a phenomenon that we term antiferromagnetic trichroism. Furthermore, using this antiferromagnetic trichroism, we successfully visualize field-driven reversal and rotation of the Néel vector. Antiferromagnets have great promise for use in spin-based electronics; however, detecting the Neel vector is challenging due to the lack of a net magnetization. Here, Kimura et al demonstrate an intriguing optical response, where the optical absorption depends on the angle of the Neel vector.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 639/301/119/1001 / 639/301/119/997 / Absorption / Absorptivity / Antiferromagnetism / Ferromagnetism / Humanities and Social Sciences / Magnetism / Magnetization / multidisciplinary / Rotation / Science / Science (multidisciplinary)