Regensburg 2002 – wissenschaftliches Programm
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MA: Magnetismus
MA 10: Poster : Dünne Schichten(1-21),Spinabh.Transp.(22-39),Exch.Bias(40-51),Spindyn.(52-55),Mikromag.(56-66),Partikel(67-74),Abb.Verf.(75-77),Oberfl.+Spinelektr.+Elektr.Theo+Mikromag(75-87),PÜ+Aniso+Werkst/Leg.(88-103),Mol.Mag.+N-dim+Messm.+Postdead(104-111
MA 10.86: Poster
Dienstag, 12. März 2002, 15:00–19:00, Bereich A
Disorder-induced magnetism in TiFexCo1−x — •Diana Benea and Hubert Ebert — Departament Chemie, University Munich, Butenandtstr. 5-13, D-81377 Muenchen, Germany
The transition metal system TiFexCo1−x has a CsCl-structure with Ti on one sublattice and a random distribution of Fe and Co according to the concentration on the other sublattice. From previous experimental investigations it was concluded that if this quasiordered structure is formed, TiFexCo1−x is in a paramagnetic state. Only if a small numbers of Fe or Co atoms (1-2%) are occupying Ti sites (so called anti-sites) the alloy system gets a weak itinerant ferromagnet for 0.2≤x≤0.8. To investigate this interesting disorder-induced magnetisation in more detail, we have used the Korringa-Kohn-Rostoker(KKR) band structure method. The disorder in the system has been accounted for by means of the Coherent Potential Approximation(CPA). Our calculations demonstrated that TiFexCo1−x is indeed paramagnetic for all concentrations x if these is no mixing of the two sublattices. Only a small mixing on the other hand gives rise to the formation of a spontaneous magnetisation that is in fairly good agreement with experiment. Our calculations give also a simple explanation for the puzzling Fe-Mößbauer data. While the Fe atoms on anti-sites have a large moment and hyperfine field, the hyperfine field of Fe-atoms on proper sites are very small because the valence band and core polarisation contributions nearly cancel another.