Chirality determination of ferromagnetic disk by local Hall effect

We report a simple and reliable detection of the vortex chirality in a single ferromagnetic disk by a local Hall effect. To improve detection sensitivity, the surface layers of a two dimensional electron gas (2DEG) are etched away and the ferromagnetic disk is positioned just 5 nm above the 2DEG channel. When an external magnetic field is applied in-plane with an angular orientation $θ=45°$ with respect to the current channel, the vortex core starts to nucleate from a different position in the disk depending on magnetic chirality, causing a stray field difference detected as the local Hall voltage. Our results show that the observed voltage kinks in the hysteresis loops are directly related to the vortex chirality. Experimental results are in good agreement with the micromagnetic simulations, which provide a strong evidence of the detection of vortex chirality.