Magnetic properties of Fe/Co(001) superlattices from first-principles theory
2006 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 74, no 17, 174409- p.Article in journal (Refereed) Published
The magnetic properties of Fe/Co(001) superlattices have been studied using fully-relativistic first-principles theories. The average magnetic moment shows a behavior similar to bulk Fe-Co alloys, i.e., an enhanced magnetic moment for low Co concentrations, as described by the Slater-Pauling curve. The maximum of the magnetization curve, however, is lowered and shifted towards the Fe-rich compositions. The increased average magnetic moment for the Fe-rich superlattices, compared to bulk Fe, is due to an enhancement of the Fe spin moment close to the Fe-Co interface. The orbital moments were found to be of the same size as in bulk. The effect of interface roughness on the magnetic properties was investigated, and it was found that-despite local fluctuations due to the varying coordination-the average magnetic moment is only slightly affected. From a mapping of first-principles interactions onto the screened generalized perturbation method, we calculate the temperatures for when Fe/Co superlattices break up into an alloy configuration. Furthermore, the tetragonal distortion of the superlattice structure was found to only have a minor effect on the magnetic moments. Also, the calculated easy axis of magnetization is in the film plane for all compositions studied. It lies along the  direction for Fe-rich superlattices and along the  direction for Co-rich compositions. The transition of the easy axis occurs around a Co concentration of 50%.
Place, publisher, year, edition, pages
2006. Vol. 74, no 17, 174409- p.
IdentifiersURN: urn:nbn:se:uu:diva-94290DOI: 10.1103/PhysRevB.74.174409ISI: 000242409000080OAI: oai:DiVA.org:uu-94290DiVA: diva2:168091