Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 23: Magnetic Thin Films II

MA 23.5: Talk

Wednesday, March 25, 2009, 15:45–16:00, HSZ 04

Analysis of intergrain interactions in epitaxial SmCo₅ thin films — •Aarti Singh, Volker Neu, Sebastian Fähler, Ludwig Schultz, and Bernhard Holzapfel — IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden, Germany

Epitaxial SmCo₅ films on MgO single crystal substrates show pinning dominated magnetization reversal. The films are known to consist of sub-100 nm sized grains with either parallel or perpendicular orientation and interactions between the grains are expected to exist. However this partially contradicts the angular dependent coercivity analysis where an independent switching of magnetizing along the individual easy axes is observed suggesting that the easy axes are decoupled. A detailed analysis was undertaken by extracting irreversible susceptibilities in the magnetizing and demagnetizing branches from recoil loop measurements. The irreversible susceptibility in the demagnetizing branch is very sharp as compared to that in the magnetizing branch which is relatively broad. We discuss this asymmetry by considering the system to be in a multi-domain state formed through interaction between neighboring grains and a largely different domain configuration in the thermally demagnetized state and saturated state. Few nucleation sites select only the strongest pinning centers to be active during the reversal mechanism which leads to the observed strong switching in the demagnetizing branch.