Layer-dependence of macroscopic and atomic magnetic correlations in Co/Pd multilayers
The development of multilayered materials with engineered magnetic properties compels a deep knowledge of physical properties at the atomic scale. The magnetic anisotropy is a key property in these materials. This work accounts for the magnetic anisotropy energy and its correlation with atomic properties of Co/Pd multilayers with the number of Co/Pd repetitions. Magnetometry measurements confirm stronger perpendicular magnetic anisotropy energies as the number of repetitions increases up to 40. However, the intrinsic anisotropy, related to the Co–Pd orbital hybridization and spin–orbit coupling, saturates at 15 repetitions. This finding is supported by x-ray magnetic circular dichroism analysis that reveals a direct correlation of the atomic Co and Pd orbital magnetic moments and the effective anisotropy of the system. The proximity effect that accounts for the Pd induced magnetization, along with the increasing Co moment, provides a suitable mechanism for the observed anisotropy energy layer dependence. ; This work received funding from the MINECO-AEI FIS2016-76058, UE FEDER "Una manera de hacer Europa"; the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant No. 734801, and the Basque Country Grant Nos. IT1162-19 and PIBA 2018-11. UPV/EHU authors are thankful for the technical and human support provided by the laser facility, x-ray service, electron microscopy, and magnetic measurement units of SGIker UPV/EHU. We acknowledge the access to BL29 at ALBA synchrotron light facility via official Proposal No. 2015091407. M.V. acknowledges funding via MINECO [Grant No. FIS2016-78591-C3-2-R (AEI/FEDER, UE)]. IMDEA Nanociencia acknowledges the support from the "Severo Ochoa" Program for Centers of Excellence in R&D (MINECO, Grant No. SEV-2016-0686). R.M. acknowledges enlightening discussions with Dr. Arturo Ponce-Pedraza (UTSA) on TEM. ; Peer reviewed