Berlin 2008 – scientific programme
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MA: Fachverband Magnetismus
MA 21: Magnetic Thin Films II
MA 21.9: Talk
Wednesday, February 27, 2008, 16:00–16:15, H 1012
Nanocrystalline epitaxial SmCo5 films with perpendicular anisotropy — •Marietta Seifert, Volker Neu, and Ludwig Schultz — IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany
Hard magnetic thin films find important applications in nano and micro electromagnetic systems (NEMS, MEMS) and magnetic recording. SmCo5 is a material with a high uniaxial magnetic anisotropy and therefore has the potential to be used as a high density recording media. Thus, in the last years, research focusses on the preparation of Sm-Co films with perpendicular anisotropy. Based on our experience on epitaxial growth of high anisotropic SmCo5 with in-plane texture we developed epitaxial SmCo5 films with strong perpendicular anisotropy by pulsed laser deposition on Ru buffered Al2O3(0001) substrates. The deposition temperature was systematically varied in a range between 550∘C and 800∘C. X-ray diffractometry shows that the SmCo5 phase develops at 550∘C and is best formed at 700∘C. Texture measurements of the (10-11) SmCo5 pole prove the perpendicular orientation of the c-axis and reveal the epitaxial growth with two different in plane orientations of the hexagonal unit cell. VSM measurements demonstrate the magnetic anisotropy with the easy axis out of plane. The sample prepared at 700∘C possesses a square shaped hysteresis loop (squareness = 0.81) with a coercivity of µ0Hc = 1.0 T. All films grow in a granular fashion with grain sizes of 100 to 300 nm. The nanocrystalline microstructure together with the local epitaxy provides the combination of highly anisotropic and well textured SmCo5 grains with good coercivity.