# Exploring antiferromagnetic domain wall mechanics through scanning nitrogen vacancy magnetometry

Hedrich, Natascha S.. Exploring antiferromagnetic domain wall mechanics through scanning nitrogen vacancy magnetometry. 2021, Doctoral Thesis, University of Basel, Faculty of Science.

 Preview
PDF

38Mb

Official URL: https://edoc.unibas.ch/84030/

We then use these improved scanning probes to study the magnetic properties of a magnetoelectric AFM: chromia. Due to its room-temperature AFM ordering and the ability to switch the magnetic order with electric fields, this material is a popular candidate for spintronics applications. In our study, we demonstrate control over the magnetic orientation of a bulk chromia (Cr$_2$O$_3$) crystal and employ its magnetoelectric properties to nucleate domain walls (DWs). Using NV magnetometry, we characterize the surface magnetization of Cr$_2$O$_3$ and investigate the DW structure. We furthermore demonstrate an interaction between the DW and patterned surface topography, allowing us to develop a model of the DW mechanics. In particular, we observe a Snell's law-like behavior of the DW in the presence of topographical steps and pinning of the DW to the edges of these steps. We use this pinning, together with local heating of the Cr$_2$O$_3$ crystal, to exert control over the motion of the DW.
These results bring us one step closer to achieving AFM-based memories. Having shown the ability to generate, control, and move DWs in an AFM crystal, we have laid the groundwork for a DW-based memory. Moreover, by improving the understanding of antiferromagnetic DW mechanics, we highlight material properties of Cr$_2$O$_3$ that may benefit and guide future material research.