Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 25: Micro- and Nanostructured Magnetic Materials II

MA 25.11: Talk

Wednesday, March 25, 2009, 17:30–17:45, HSZ 403

(001) textured FePt thin films on spherical SiO₂ nanoparticle template — Christoph Brombacher¹, •Christian Schubert¹, Andreas Teichgräber¹, Sara Romer-Urban², Mireille Maret³, Denys Makarov⁴, Michael Hietschold¹, and Manfred Albrecht¹ — ¹Institute of Physics, TU Chemnitz, Chemnitz, Germany — ²Nanoscale Materials Science, Empa, Dübendorf, Switzerland — ³Laboratoire de Thermodynamique et Physico-Chimie Métallurgiques, ENSEEG, Saint Martin d’Heres, France — ⁴Department of Physics, University of Konstanz, Konstanz, Germany

Due to its high magnetocrystalline anisotropy and excellent corrosion resistance, FePt is considered one of the most promising candidates for future magnetic data storage devices. In this study, densely-packed arrays of SiO₂ nanoparticles have been used as a template to create regular FePt nanostructures suitable for application as patterned media. The sputter deposited FePt film displays a chemically disordered fcc phase. Postannealing in a commercial RTA setup yields both a high ordering parameter and the desired (001) texture as shown by XRD and TEM. The heating rate, heating time and heating temperature have been optimized on planar SiO₂ substrates, obtaining perpendicular magnetic anisotropy and coercivities of up to 2 T. Furthermore, the FePt films exhibit a strong dewetting behavior on both planar substrates and spherical nanoparticles. By tuning the thickness of the FePt layer, the characteristic length scales of the dewetting process can be controlled. This was used to create isolated FePt nanostructures on SiO₂ particle arrays with periodicities down to 50 nm.