Berlin 2008 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 25: SYM Thin Film Magnetic Materials: Microstructure, Reaction and Magnetic Coupling IV

MM 25.4: Vortrag

Mittwoch, 27. Februar 2008, 17:10–17:30, H 1058

Strain effect on spin reorientation of epitaxial Nd-Fe-B films — •Ah-Ram Kwon¹, Volker Neu¹, Vlakimir Matias², Jens Hänisch², Ruben Hühne¹, Bernhard Holzapfel¹, Ludwig Schultz¹, and Sebastian Fähler¹ — ¹IFW Dresden, P.O. Box 270116, D-01171 Dresden — ²Los Alamos National Laboratory, Mail Stop T004, Los Alamos NM 8545 USA

Nd-Fe-B is the best permanent magnetic materials known to date. Thin film applications such as magnetic microactuators and motors as well as the study of intrinsic properties require well textured Nd-Fe-B films. Here a new approach to study the influence of strain on the intrinsic magnetic properties, especially spin reorientation transition is demonstrated. Hastelloy, which has high ductility, is used as substrate to reach a strain up to 2% by conventional mechanical elongation. Prior to elongation, MgO(001) had been deposited by ion beam assisted deposition. As a next step Mo and Nd-Fe-B are deposited at 450 °C by pulsed laser deposition. Mo grows epitaxially with a (001) orientation and Nd-Fe-B films onto this buffer possess the desired (00l) out-of-plane orientation. Elongation breaks the symmetry compared to the as-deposited state, resulting in an elliptical shape of the cone opening during spin reorientation. By this novel approaches high strains are obtained which allows to examine highly anisotropic materials where magnetostriction can usually be neglected.