New Imaging Technique for Antiferromag­netic Spintronics

Helena Reichlova, Tomas Janda, Joao Godinho, Anastasios Markou, Dominik Kriegner, Richard Schlitz, Jakub Zelezny, Zbynek Soban, Mauricio Bejarano, Helmut Schultheiss, Petr Nemec, Tomas Jungwirth, Claudia Felser, Joerg Wunderlich & Sebastian T. B. Goennenwein

Non-collinear antiferromagnets (nc AFMs) are an increasingly important part of antiferromagnetic spintronics. Many effects known only from ferromagnets were recently observed also in nc AFMs, and even a spin transfer torque via spin polarized current is theoretically predicted to be present in these materials. To experimentally observe and study these phenomena, a simple and robust technique to image and write magnetic structures (magnetic domains) into nc-AFM is required.

Here, we present scanning thermal gradient microscopy as a tool to visualize magnetic configurations in nc-AFM Mn₃Sn thin films. The technique is based on a laser induced thermal gradient which is scanned over the sample surface. The out-of-plane thermal gradient generates an in-plane thermo-voltage via the anomalous Nernst effect, which depends on the domain orientation and therefore yields magnetic spatial contrast. We further show that the domain patterns can be modified via heat assisted writing. Our work opens a route not

 only to image domains in nc-AFMs but also to prepare well-defined domain configurations. We used Mn₃Sn as a model system; however, the technique is applicable to any material with magneto-thermal response, in particular including thin film multilayers.   

Original publication: Nature Comm. 10, 5459 (2019)