Skyrmions and Anomalous Hall Effect in a Dzyloshinskii-Moriya Spiral Magnet

Abstract

Monte Carlo simulation study of a classical spin model with Dzylosinskii-Moriya interaction and the spin anisotropy under the magnetic field is presented. We found a rich phase diagram containing the multiple spin spiral (or skyrme crystal) phases of square, rectangular, and hexagonal symmetries in addition to the spiral spin state. The Hall conductivity ${\sigma }_{xy}$ is calculated within the $sd$ model for each of the phases. While ${\sigma }_{xy}$ is zero in the absence of external magnetic field, applying a field strength $H$ larger than a threshold value $H_c$ leads to the simultaneous onset of nonzero chirality and Hall conductivity. We find $H_c=0$ for the multiple spin spiral states, but $H_c>0$ for a single spin spiral state regardless of the field orientation. Relevance of the present results to MnSi is discussed.

References in corpus (2)

• Chirality induced anomalous-Hall effect in helical spin crystals
• Crystalline phases in chiral ferromagnets: Destabilization of helical order