Disorder-induced microscopic magnetic memory

TL;DR

This study uses coherent x-ray speckle metrology to investigate how disorder affects microscopic magnetic memory in Co/Pt multilayer films, revealing the onset and saturation of memory with increasing disorder.

Contribution

First direct experimental measurement of disorder's effect on microscopic magnetic memory in multilayer films, comparing results with existing theories.

Findings

Memory absent at low disorder

Memory increases with disorder and saturates

Experimental results align with theoretical predictions

Abstract

Using coherent x-ray speckle metrology, we have measured the influence of disorder on major loop return point memory (RPM) and complementary point memory (CPM) for a series of perpendicular anisotropy Co/Pt multilayer films. In the low disorder limit, the domain structures show no memory with field cycling--no RPM and no CPM. With increasing disorder, we observe the onset and the saturation of both the RPM and the CPM. These results provide the first direct ensemble-sensitive experimental study of the effects of varying disorder on microscopic magnetic memory and are compared against the predictions of existing theories.