Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 21: Magnetic Materials

MA 21.3: Vortrag

Mittwoch, 24. März 2010, 15:45–16:00, H23

Disorder Effects on the Magneto-Crystalline Anisotropy Energy of Strained Fe-Co Alloys — •Carsten Neise, Stephan Schönecker, Manuel Richter, Klaus Koepernik, and Helmut Eschrig — IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany

Tetragonally distorted Fe_1−xCo_x alloys recently attracted interest due to their potential applicability as new media for high density recording, combining a large uniaxial Magneto-Crystalline Anisotropy with a large saturation magnetisation for certain chemical compositions x and certain tetragonal distortions. Previous calculations by Burkert et. al. [Phys. Rev. Lett. 93, 027203 (2004)] disregarded volume relaxation, which is present in epitaxially grown layers and may alter the magnetic properties of these alloys. We investigated this and the influence of disorder on the MCA and on the magnetic moment of Fe_1−xCo_x alloys along the epitaxial Bain path. Two different methods were used to describe disorder, (i) the virtual crystal approximation, and (ii) a stochastic average of supercells with randomly distributed atoms. Comparison with the ordered structures of the L1₀ and the L1₂ phases reveals the impact of disorder on the magnetic properties. We employed the full potential local orbital program package FPLO [http://www.fplo.de] for our density functional calculations.