Disorder-induced antiferromagnetic to ferromagnetic transition in magneticoverlayers: (Fe,Mn)/W(001) as a case study

0357426 - FZÚ 2011 RIV JP eng J - Journal Article
Kudrnovský, Josef - Ondráček, Martin - Bengone, O. - Máca, František
Disorder-induced antiferromagnetic to ferromagnetic transition in magneticoverlayers: (Fe,Mn)/W(001) as a case study.
e-Journal of Surface Science and Nanotechnology. Roč. 8, - (2010), s. 184-189. ISSN 1348-0391
R&D Projects: GA ČR GA202/07/0456; GA MŠMT OC09028; GA ČR GA202/09/0775
Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521
Keywords : ab initio calculations * Green’s function methods * construction of effective interatomic interactions * magnetic phase transitions in overlayers
Subject RIV: BM - Solid Matter Physics ; Magnetism

The magnetic phase stability of the random FexMn1-x monolayer on the bcc-W(001) substrate is studied from first-principles. The exchange interactions among two-types of magnetic atoms in the overlayer are estimated and used to construct the random classical two-dimensional Heisenberg Hamiltonian. The stability of such effective Hamiltonian is then studied with respect to a broad class of magnetic arrangements which include also possible spin-spiral structures. We have found that exchange interactions between Fe-spin are antiferromagnetic while those between Mn-spins are ferromagnetic over the whole concentration range. This pronounced frustration leads to a complex behavior in which the c(2x2) antiferromagnetic state for Fe-monolayer goes over to complex incommensurate spin-spiral magnetic structures with increasing Mn-content. A spin-spiral state with a large period was found also for the Mn-monolayer case in agreement with a recent experiment.
Permanent Link: http://hdl.handle.net/11104/0195705