Observation of domain wall segment jump among disorders

Abstract

In creep regime, a magnetic domain wall (DW) is regarded as a one-dimensional object that consists of many small segments. However, observation of such a specific segment motion has remained a challenge due to its small size. Here we present direct evidence of individual DW segment motion by employing electrical Hall measurement. When the DW is moved by a weak magnetic field, we find that the anomalous Hall effect (AHE) resistance, R-AHE, exhibits random jumps between two resistance states. We confirm that the R-AHE jump appears in various samples but the R-AHE jump is absent when the width of sample is narrower than DW jump size. These results imply the existence of a specific segment length that governs the DW creep motion.