First-principles study of thermodynamical properties of random magnetic overlayers on fcc-Cu(001) substrate
2013 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 87, no 7, 075452- p.Article in journal (Refereed) Published
We present a theoretical study of the thermodynamical properties of a fcc-Cu(001) substrate covered by an iron-cobalt monolayer as well as by an incomplete iron layer. The effective two-dimensional Heisenberg Hamiltonian is constructed from first principles and the properties of exchange interactions are investigated. The Curie temperatures are estimated using the Monte Carlo (MC) simulations and compared with a simplified approach using the random-phase approximation (RPA) in connection with the virtual-crystal approach (VCA) to treat randomness in exchange integrals. Calculations indicate a weak maximum of the Curie temperature as a function of composition of the iron-cobalt overlayer. While a good quantitative agreement between RPA-VCA and MC was found for the iron-cobalt monolayer, the RPA-VCA approach fails quantitatively for low coverage due to the magnetic percolation effect. We also present a study of the effect of alloy disorder on the shape of magnon spectra of random overlayers.
Place, publisher, year, edition, pages
2013. Vol. 87, no 7, 075452- p.
Exchange Interactions, Curie-Temperature, Alloys
IdentifiersURN: urn:nbn:se:kth:diva-119731DOI: 10.1103/PhysRevB.87.075452ISI: 000315482500011ScopusID: 2-s2.0-84874514868OAI: oai:DiVA.org:kth-119731DiVA: diva2:612780
FunderSwedish e‐Science Research CenterSwedish Research Council
QC 201303252013-03-252013-03-212013-03-25Bibliographically approved