Quasistatic x-ray speckle metrology of microscopic magnetic return point memory

TL;DR

This study uses resonant x-ray magnetic speckle patterns to analyze microscopic magnetic domain behavior and return point memory in perpendicular magnetic films, highlighting the role of interfacial roughness.

Contribution

First direct ensemble-averaged measurement of microscopic magnetic return point memory using x-ray speckle patterns, revealing the influence of interfacial roughness.

Findings

Microscopic magnetic domains forget their history exponentially with field.

Interfacial roughness significantly affects magnetic return point memory.

First direct measurement of this phenomenon at the microscopic level.

Abstract

We have used coherent, resonant, x-ray magnetic speckle patterns to measure the statistical evolution of the microscopic magnetic domains in perpendicular magnetic films as a function of the applied magnetic field. Our work constitutes the first direct, ensemble-averaged study of microscopic magnetic return point memory, and demonstrates the profound impact of interfacial roughness on this phenomenon. At low fields, the microscopic magnetic domains forget their past history with an exponential field dependence.