Asymmetric magnetic bubble expansion under in-plane field in Pt/Co/Pt: effect of interface engineering

TL;DR

This study investigates how growth conditions affect asymmetric magnetic bubble expansion in ultrathin Pt/Co/Pt films, revealing discrepancies with existing theories and highlighting the need for advanced models of domain-wall behavior.

Contribution

It demonstrates the influence of interface engineering on magnetic properties and uncovers limitations of current domain-wall propagation theories under in-plane fields.

Findings

Growth conditions significantly alter interfacial structure.

Effective perpendicular magnetic anisotropy varies with sputtering Ar pressure.

Experimental results challenge existing domain-wall propagation models.

Abstract

We analyse the impact of growth conditions on asymmetric magnetic bubble expansion under in-plane field in ultrathin Pt / Co / Pt films. Specifically, using sputter deposition we vary the Ar pressure during the growth of the top Pt layer. This induces a large change in the interfacial structure as evidenced by a factor three change in the effective perpendicular magnetic anisotropy. Strikingly, a discrepancy between the current theory for domain-wall propagation based on a simple domain-wall energy density and our experimental results is found. This calls for further theoretical development of domain-wall creep under in-plane fields and varying structural asymmetry.