Identifying the octupole antiferromagnetic domain orientation in Mn3NiN by scanning anomalous Nernst effect microscopy

Johnson, F. et al. (2022) Identifying the octupole antiferromagnetic domain orientation in Mn3NiN by scanning anomalous Nernst effect microscopy. Applied Physics Letters, 120, 232402. (doi: 10.1063/5.0091257)

Abstract

The intrinsic anomalous Nernst effect in a magnetic material is governed by the Berry curvature at the Fermi energy and can be realized in non-collinear antiferromagnets with vanishing magnetization. Thin films of (001)-oriented Mn3NiN have their chiral antiferromagnetic structure located in the (111) plane facilitating the anomalous Nernst effect unusually in two orthogonal in-plane directions. The sign of each component of the anomalous Nernst effect is determined by the local antiferromagnetic domain state. In this work, a temperature gradient is induced in a 50 nm thick Mn3NiN two micrometer-size Hall cross by a focused scanning laser beam, and the spatial distribution of the anomalous Nernst voltage is used to image and identify the octupole macrodomain arrangement. Although the focused laser beam width may span many individual domains, cooling from room temperature to the antiferromagnetic transition temperature in an in-plane magnetic field prepares the domain state, producing a checkerboard pattern resulting from the convolution of contributions from each domain. These images together with atomistic and micromagnetic simulations suggest an average macrodomain of the order of 1 μm2.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Boldrin, Dr David
• Authors: Johnson, F., Kimák, J., Zemen, J., Šobáň, Z., Schmoranzerová, E., Godinho, J., Němec, P., Beckert, S., Reichlová, H., Boldrin, D., Wunderlich, J., and Cohen, L. F.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Applied Physics Letters
• Publisher: AIP Publishing
• ISSN: 0003-6951
• ISSN (Online): 1077-3118
• Published Online: 08 June 2022
• Copyright Holders: Copyright © The Author(s) 2022
• First Published: First published in Applied Physics Letters 120: 232402
• Publisher Policy: Reproduced under a Creative Commons licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
307066		New Caloric Materials for Energy Efficient Refrigeration	Donald Maclaren	Leverhulme Trust (LEVERHUL)	ECF-2019-351	P&S - Physics & Astronomy