Dresden 2011 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 11: Thin Film Characterisation: Structure Analysis and Composition (XRD, TEM, XPS, SIMS, RBS, ...) IV
DS 11.3: Vortrag
Montag, 14. März 2011, 16:15–16:30, GER 38
Structure of FePt thin films with copper addition — •Herbert Schletter, Christoph Brombacher, Manfred Albrecht, and Michael Hietschold — Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz
The continuous increase in storage density of magnetic hard disk drives creates a need for new concepts and new materials in this field. One approach is the use of highly anisotropic materials which allow for further reduction of bit sizes. One of these materials is the L10 phase of FePt. However, a thermal treatment of the material (either during or after the deposition) is necessary to (i) transform the material from cubic A1 to tetragonal L10 phase and (ii) create a (001)-textured film, for which the magnetic anisotropy axis is perpendicular to the film plane.
In our experiments, different amounts of Cu (up to 21 at.%) were added to 5 nm thick FePt layers to support the phase transformation as well as the texture evolution during rapid thermal annealing (RTA) [1]. The structure of these layers was investigated by means of TEM and electron diffraction combined with multislice simulations. It was found, that pure FePt layers consist of a mixture of untextured A1-FePt and (001)-textured L10-FePt after RTA to 600 ∘C for 30 s. In this case, the A1-phase is encountered in significantly smaller grains (≈ 10 nm) than the L10-phase (≈ 50 nm). However, the addition of ≥ 9 at.% Cu leads to pure L10-FePt:Cu films with the desired (001)-texture when applying the same annealing parameters.
[1] D. Makarov et al., Appl. Phys. Lett. 96, 062501 (2010)