Sublattice magnetizations of ultrathin ferrimagnetic lamellar nanostructures between cobalt leads

Abstract

In this work we model the salient magnetic properties of the alloy lamellar ferrimagnetic nanostructures $[Co_{1-c}Gd_c]_{\ell^{\prime}}[Co]_\ell[Co_{1-c}Gd_c]_{\ell^{\prime}}$ between $Co$ semi-infinite leads. We have employed the Ising spin effective field theory (EFT) to compute the reliable magnetic exchange constants for the pure cobalt $J_{Co-Co}$ and gadolinium $J_{Gd-Gd}$ materials, in complete agreement with their experimental data. The sublattice magnetizations of the $Co$ and $Gd$ sites on the individual hcp atomic (0001) planes of the $Co-Gd$ layered nanostructures are computed for each plane and corresponding sites, by using the combined EFT and mean field theory (MFT) spin methods. The sublattice magnetizations, effective site magnetic moments, and ferrimagnetic compensation characteristics for the individual hcp atomic planes of the embedded nanostructures, are computed as a function of temperature, and for various stable eutectic concentrations in the range $c\leq$ 0.5. The theoretical results for the sublattice magnetizations and the local magnetic variables of these ultrathin ferrimagnetic lamellar nanostructured systems, between cobalt leads, are necessary for the study of their magnonic transport properties, and eventually their spintronic dynamic computations. The method developed in this work is general and can be applied to comparable magnetic systems nanostructured with other materials.