Chirality readout of antiferromagnetic topological spin textures via quantum magnetometry

The recent discovery of ambient topological spin textures in the classical antiferromagnet (AF) α-Fe₂O₃ is a tremendous leap towards realizing AF spintronics. The presence of bulk Dzyaloshinskii-Moriya interaction in this AF system produces a small uncompensated magnetic moment generating weak stray fields (μT) which remains unexplored. In this study, we show for the first time the characteristic stray-field signature of various nanoscale AF topological quasiparticles with scanning NV magnetometry (SNVM). We evidence merons, antimerons and anti-phase domain walls above and below the Morin temperature (T_M=200 K), and crucially demonstrate direct chirality readout. Remarkably, simulations and observed field signatures also suggest a magnetic charge imprint on topological AF quasiparticles. The table-top nanoscale imaging of two-dimension AF quasiparticles underlines the increasingly vital role of SNVM in accelerating research in the AF spintronics.