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MA: Magnetismus

MA 2: Magnetic Thin Films I

MA 2.8: Vortrag

Montag, 27. März 2006, 12:00–12:15, HSZ 03

The temperature dependent magnetization process in small CoPt stripes observed by low temperature MFM — •Ulrike Wolff¹, Christoph Hassel², Mario Brands², Günther Dumpich², Ludwig Schultz¹, and Volker Neu¹ — ¹IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden, Germany — ²Universität Duisburg-Essen, Standort Duisburg, Institut für Physik, AG Farle, Lotharstr. 1, 47048 Duisburg, Germany

In small structured CoPt stripes the magnetoresistive behaviour is governed by a combination of anisotropic magnetoresistance and domain wall resistance. In order to support the interpretation of magnetoresistive measurements, in this work the magnetization process in CoPt stripes with perpendicular magnetic anisotropy and varying stripe width of 300 to 2200 nm was investigated by low temperature magnetic force microscopy. At various temperatures the CoPt stripes were magnetized in a field of 1 T and MFM measurements were subsequently performed during demagnetizing field sweeps. The locally determined coercive field increases from 0.07 T at 238 K to 0.23 T at 10 K. Whereas the coercivity does not depend strongly on the stripe width, the magnetization process is strongly different for narrow and wide CoPt stripes. At 10 K the 300 nm narrow stripes switch via the nucleation of a reversed domain over the whole width of the stripe. The wider stripes form a more complicated, two dimensional domain pattern during magnetization reversal.