Spin-hedgehog-derived electromagnetic effects in itinerant magnets

Abstract

In itinerant magnets, the indirect exchange coupling of Ruderman-Kittel-Kasuya-Yosida type is known to stabilize incommensurate spin spiral. Whereas an account of higher order spin interactions favors the formation of a noncoplanar magnetic texture. This is manifested by the finite Berry phase the conduction electrons accumulate when their spins follow this texture, leading thus to the topological Hall effect. We herein utilize the effective spin model with bilinear-biquadratic exchange interactions for studying the formation of the magnetic hedgehog lattice in a three-dimensional itinerant magnet. As opposed to widely used Monte Carlo simulations, we employ a neural-networkbased approach for exploring the ground state spin configuration. Further, we address the topological Hall conductivity and magneto-optic Kerr effect in the itinerant magnet due to the coupling to the spin hedgehog lattice.