Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Magnetic Thin Films I

MA 17.3: Vortrag

Mittwoch, 25. März 2009, 10:45–11:00, HSZ 04

Tailoring the FePt orientation on amorphous substrates by magnetron sputtering - Structural and magnetic investigations — •valentina cantelli, johannes von borany, jörg grenzer, and jürgen fassbender — Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, Dresden, Germany

High magnetocrystalline (001) oriented L1₀ FePt layers are widely studied for perpendicular recording magnetic media. We will report about the tuning of FePt (001) orientation using Ar and Xe gases, onto a-SiO₂/Si substrates by magnetron sputtering deposition at 0.3 Pa. Layer-by-layer and co-deposition were investigated comparatively. Thin (∼12 nm) Fe₅₅Pt₄₅ layers were deposited at RT, subsequently annealed at 750^∘C to induce the A1-L1₀ ordering transformation. Sputtering in Ar delivers energetic particles (∼ 12 eV sputtered Fe or Pt atoms and ∼ 100 eV Ar reflected neutrals from Pt target). This energy budget enhances surface adatom mobility, creates vacancies [1], and supports vertical intermixing into the layer, during deposition. At RT, a randomly oriented crystalline FePt A1 structure is produced. After annealing, the L1₀ phase is obtained with coercive field H_C = 20 kOe and weak (001) orientation, irrespective of deposition methods. Sputtering in Xe significantly reduces energetic impacts from backscattered neutrals. Using a layer-by-layer deposition, L1₀ films have H_C = 5.6 kOe with the lowest (∼ 2.5^∘) angular dispersion around the (001) direction. [1] V. Cantelli, J. von Borany, A. Mucklich, Shengqiang Zhou, J. Grenzer, Nucl. Instr. and Meth. B 257, (2007) 406