Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Magnetic Coupling Phenomena

MA 18.5: Vortrag

Dienstag, 1. April 2014, 15:00–15:15, HSZ 403

Exchange bias and long-range interlayer coupling in Co/Mn/Co trilayers — •Bin Zhang, Chii-Bin Wu, and Wolfgang Kuch — Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Epitaxial Co/Mn/Co trilayers with a wedged Mn layer were grown on Cu(001) to study the exchange bias and interlayer coupling by magneto-optical Kerr effect measurements. The coercivity of the trilayers as a function of thickness starts to increase at around 4.7 ML. Exchange bias appears around 10 ML. The hysteresis loops exhibit two separate steps above 10 ML Mn thickness, corresponding to the switching of the two FM layers. From minor loop measurements both the coercivity and the remanence of the top Co layer have been determined. Both show an oscillation with 1 ML period as a function of the Mn layer thickness. We attribute this to roughness oscillations at the upper interface due to the layer-by-layer growth of Mn on Co. The magnetic coupling of the top and bottom Co layer through the Mn layer exhibits an oscillation with a period of 2 ML Mn thickness above a thickness of 10 ML. In addition, a long-period interlayer coupling of the two FM layers with antiparallel coupling maxima at Mn thicknesses of 2.5, 8.2, and 13.7 ML is observed and attributed to RKKY-type coupling. There is no oscillatory behavior of the exchange bias in the bottom layer.