Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 27: Micro- and Nanostructured Magnetic Materials II

MA 27.5: Talk

Thursday, March 29, 2007, 16:15–16:30, H22

Switching behaviour of patterned SmCo thin films investigated by magnetic force and magneto optical microscopy — •Ulrike Wolff¹, Sebastian Dreyer², Aarti Singh¹, Christian Jooss², Ludwig Schultz¹, and Volker Neu¹ — ¹IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany — ²Institute for Materials Physics, University Göttingen, Germany

SmCo₅ thin films with a strong magnetic anisotropy are prepared epitaxially on Cr buffered MgO(110) and MgO(100) substrates either with a unique alignment of the c-axis throughout the film or with two perpendicular orientations of the easy axes in the film plane [1]. For magnetic force microscopy (MFM) and magneto optical indicator film (MOIF)measurements, patterned elements were magnetized up to 4 T to adjust different remanent states and afterwards the domain structure was imaged. In the thermally demagnetized state magnetic contrast is visible on a length scale of 200 nm, which is about 4-5 times larger than the size of the individual grains. Thus, one has to describe the magnetic state by interaction domains originating from exchange or dipolar coupling of neighbouring grains. Upon applying an external field, the stray field contrast inside the element reduces and magnetic charges of opposite sign build up at the two edges of the squares perpendicular to the field direction. The domain structure resolved by MFM is compared with the quantitative stray field measurements obtained by MOIF.

[1] A. Singh et al, APL 87, 072505 (2005)