Investigation of Domain Walls in Single Crystal Cr₂O₃ Using Nitrogen Vacancy Scanning Magnetometry

Magnetoelectric antiferromagnets are promising candidates for spintronic devices that have been used to demonstrate electrical reading and writing [1]. Chromia, in particular, has drawn attention due to its room temperature ordering. While domain structures in thin-film Cr₂O₃ have been studied in detail [2], domains in single crystals prove more elusive and less well understood. Second harmonic generation and magnetic force microscopy have been used to study these structures, but these techniques have provided primarily qualitative images [3,4]. Here, we present a quantitative study of domain walls in single crystal chromia using nitrogen vacancy (NV) magnetometry, performed with all-diamond scanning probes, where we make use of the sub 1 uT/√Hz sensitivity and sub 50 nm spatial resolution of these structures to investigate the domain wall properties at the nanoscale. Our measurements demonstrate the unique possibility offered by NV magnetometry to study single crystalline antiferromagnetic systems and reveal fundamental properties of the crystal and its spin textures.


References
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2. P. Appel, et.al., Nano Lett. 19, 3 (2019).
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4. P. Schoenherr, et.al., Materials, 10 1051 (2017).