Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 1: Invited Talk Lyubina
MA 1.1: Hauptvortrag
Montag, 26. März 2007, 09:30–10:00, H10
Magnetovolume effects in L10 Fe-Pt alloys — •Julia Lyubina1, Ingo Opahle1, Manuel Richter1, Olivier Isnard2, Oliver Gutfleisch1, Karl-Hartmut Müller1, and Ludwig Schultz1 — 1IFW Dresden, P.O. Box 270016, D-01171 Dresden, Germany — 2Laboratoire de Cristallographie, CNRS, Université J. Fourier Grenoble and Institut Laue-Langevin, 38042 Grenoble cedex 9, France
FePt alloys have recently attracted considerable attention as candidates for ultra-high-density magnetic storage media and as materials for special permanent magnet applications. The excellent magnetic properties of these alloys are associated with the ordered L10 FePt phase. Both experimental data and theoretical calculations indicate a correlation between the degree of order within the L10 phase and fundamental properties, such as magnetocrystalline anisotropy and Curie temperature. In contrast, the saturation magnetisation of the L10 phase was reported to be largely independent of the degree of order at a fixed composition. In this work, we report on a combined neutron powder diffraction and density functional study of ordered and partially ordered Fe100−xPtx (x = 41-52) alloys prepared by mechanical alloying at 77 K and subsequent heat treatment. For alloys with almost perfect L10-type long-range order the experimental value of the Fe magnetic moment was determined to be 2.8 ± 0.1 µB. It is shown that the Fe moment drops with increasing Fe content, but is less sensitive to the degree of order.