Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 18: Magnetic Thin Films II

MA 18.15: Talk

Wednesday, March 24, 2010, 19:00–19:15, H3

MOKE spectroscopy of FePtCu thin films with perpendicular magnetic anisotropy — •Michael Fronk, Lars Smykalla, Christoph Brombacher, Christian Schubert, Manfred Albrecht, and Georgeta Salvan — Chemnitz University of Technology

Since the uniaxial magnetic anisotropy of FePt in its chemically ordered L1₀ phase can reach 10 MJ/m³ FePt is considered to be a promising material for future magnetic storage devices. In this work Fe₅₂Pt₄₈(5 nm – x)/Cu(x) bilayers have been sputter deposited at room temperature onto thermally oxidized Si wafers and afterwards annealed to various temperatures between 450^∘C and 800^∘C under N₂ atmosphere using a commercial rapid thermal annealing (RTA) setup. The RTA procedure leads to the formation of a ternary FePtCu alloy with pronounced perpendicular magnetic anisotropy. The dependence of both the coercivity and remanence extracted from polar MOKE hysteresis loops at 1.96 eV on the annealing temperature will be discussed with respect to the initial Cu thicknesses of 0.5 nm and 0.9 nm. In addition, MOKE-spectroscopy in the energy range between 1.7 eV and 5.5 eV was performed and a clear dependence on the initial Cu thickness and the annealing temperature is found. In some of the spectra the main spectral feature at around 2 eV exhibits a fine structure, which could be caused by the coexistence of the two crystalline phases and/or by the presence of defect sites.