Long-range modulation of skyrmion population by local current injection

Abstract

The thin-film magnetic skyrmion is designed to interact with each other as nonlinear response, enabling collective magnetic morphology at the nonequilibrium state. We here explore the alternative nonlinear morphology of multiple skyrmions induced by the orthogonal two-current injections for the Pt/Co/Ir multilayer platforms. The global currents induce polarity-dependent driving and accumulation of skyrmions across the whole area of a Hall bar device. Once another local current is injected from a μm width port, dozens of skyrmions follow their polarity manners of the local injection, resulting in total modulations of skyrmion population governed by a pair of two-current polarities. Such massive morphology tuning at the nonlinear region indicates resemblances with a skyrmion Hall effect, where current-induced accumulation and depletion create the nonequilibrium distributions of skyrmions toward Hall deflections. Our findings propose an alternative controlling method of skyrmion population through threshold-like responses.