Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 18: Magnetic Coupling Phenomena

MA 18.3: Talk

Tuesday, April 1, 2014, 14:30–14:45, HSZ 403

Mapping techniques with MOKE on FeMn/Co-exchange bias samples — Mathias Schmidt, Joachim Gräfe, Eberhard Goering, and •Gisela Schütz — Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart

Exchange bias (EB)-systems are very important for several applications in the area of magnetic storage and spintronics. Inside that class of materials, FeMn/Co thin films are one of the most prominent examples. We used molecular beam epitaxy (MBE) to produce FeMn/Co-systems on (100)-MgO substrates. Since the EB effect is very sensitive to sample properties like layer thickness, roughness and also layer composition which can significantly deviate laterally on co-evaporated films like FeMn, a fast and spatially resolving measuring technique is very useful for a fast and reliable local characterization of the magnetic reversal process. For that issue, we used two applications of the magneto-optic Kerr effect (MOKE), delivering a sub-micrometer resolution and the possibility to measure a full hysteresis loop of a magnetic system in a timescale of milliseconds. At first, we will present maps of magnetic properties like exchange bias and coercive fields using the recently developed sweep-map-technique , an extremely fast method for magnetic sample characterization on a lateral scale up to several millimeters. Furthermore, we will show several examples of measurements with the FORC (first-order reversal-curve)-technique, delivering a dataset of all magnetic states of a system in a two dimensional contour plot and therefore revealing the distribution of local coercive fields and interactions (i.e. exchange bias) in our samples.