Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)

MA 40.25: Poster

Friday, March 27, 2009, 11:00–14:00, P1A

The effect of the sputtering gas (Ar, Xe) on FePt clusters formation, structural and magnetic properties — •valentina cantelli, jörg grenzer, johannes von borany, and jürgen fassbender — Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, Dresden, Germany

L1₀ FePt phase is widely studied for magnetic recording media because of an excellent magnetocrystalline anisotropy (K_U ∼ 5-8 × 10⁻⁷ erg/cm³) and large magnetic moments. [1] We will report about the effect of the sputtering gases, Ar and Xe, on FePt clusters formation using magnetron sputtering deposition at high working pressures. Sequential monolayers or co-deposition have been investigated comparatively. 5 or 3 nm thick layers were deposited at RT onto SiO₂/Si substrates, subsequently annealed at 550^∘C in order to induce the A1-L1₀ ordering transformation. The highest L1₀ fraction was found using Xe as sputtering gas. Xe ions impact enhances layers coarsening in as-deposited films: 2 nm crystallites agglomerate in clusters having a lateral size of about 50 nm; and decreases the transformation activation energy reducing the critical thickness for the ordering transition. Layers deposited with Ar as sputter gas show an almost close morphology. Strong ferromagnetic behavior has been obtained only in the case of a sequential monolayers deposition, underlining the importance to reduce the diffusion path to an atomistic scale. [2]

[1] H. Kanazawa, G. Lanhoff, T. Suzuki, J. Appl. Phys. 87 (2000) 6143; [2] M. L. Yan, N. Powers, D. J. Sellmyer, J. Appl. Phys. 93 (2003) 8292