Magnetic relaxation of exchange biased (Pt/Co) multilayers studied by time-resolved Kerr microscopy

TL;DR

This study investigates the magnetization relaxation in exchange biased (Pt/Co) multilayers with perpendicular anisotropy using time-resolved Kerr microscopy, revealing asymmetric nucleation behavior influenced by local inhomogeneities.

Contribution

It provides new insights into the magnetization reversal mechanisms in exchange biased multilayers, highlighting the role of local inhomogeneities in the exchange bias field.

Findings

Nucleation density is higher for the descending field branch.

Magnetization reversal involves nucleation and domain wall propagation.

Local inhomogeneities influence the asymmetry in reversal behavior.

Abstract

Magnetization relaxation of exchange biased (Pt/Co)5/Pt/IrMn multilayers with perpendicular anisotropy was investigated by time-resolved Kerr microscopy. Magnetization reversal occurs by nucleation and domain wall propagation for both descending and ascending applied fields, but a much larger nucleation density is observed for the descending branch, where the field is applied antiparallel to the exchange bias field direction. These results can be explained by taking into account the presence of local inhomogeneities of the exchange bias field.