Magnetization reversal ofCo∕Ptmultilayers: Microscopic origin of high-field magnetic irreversibility

Joseph E. Davies, Olav Hellwig, Eric E. Fullerton, Greg Denbeaux, J. B. Kortright, Kai Liu
2004 Physical Review B  
Title Magnetization reversal of Co/Pt multilayers: Microscopic origin of high-field magnetic irreversibility Permalink Journal Physical Review B, 70(22) We investigate the magnetization reversal in [Co(4Å)/Pt(7Å)] 50 multilayers with perpendicular magnetic anisotropy both macroscopically by First Order Reversal Curve (FORC) technique and microscopically by Transmission X-Ray Microscopy (TXRM) and resonant x-ray Small Angle Scattering (SAS). In
more » ... , we focus on the nucleation and saturation processes. The onset of magnetization reversal is dominated by irreversible processes corresponding to the avalanche-like propagation of 1-dimensional stripe domains that originate from earlier nucleated 0-dimensional bubble domains. In a second stage we observe mainly reversible behavior where the overall domain topology is preserved. Finally another irreversible process brings the sample to negative saturation, corresponding to the contraction and annihilation of domains. Interestingly, even well beyond the apparent major-loop saturation field, the FORC diagram exhibits pronounced irreversible switching and thus provides a direct measure of the true (and significantly higher) saturation field. TXRM and SAS measurements reveal on a microscopic level that some residual bubble domains with negligible moments still persist for fields well above the apparent saturation field. These residual domains, if un-annihilated, significantly alter the subsequent magnetization reversal.
doi:10.1103/physrevb.70.224434 fatcat:huye7qynqjgpthese5vu2lo4dm