Berlin 2012 – scientific programme

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MA: Fachverband Magnetismus

MA 13: Magnetic Materials

MA 13.5: Talk

Monday, March 26, 2012, 16:00–16:15, H 0112

Giant Magnetoimpedance Effect in Composite Wires with Insulating Layer — •Ralf Betzholz¹, Haibin Gao¹, Zhenjie Zhao², and Uwe Hartmann¹ — ¹Institute of Experimental Physics, Saarland University, P.O.Box 151150, D-66041 Saarbrücken, Germany — ²Department of Physics, East China Normal University, 3663 Zhongshan North Road, 200062 Shanghai, P.R. China

Composite wires with a three-layered structure were analysed with respect to the giant magnetoimpedance (GMI) effect. The composite wire samples consist of a copper core, a silicon dioxide insulating layer and an outer Permalloy shell. The GMI effect refers to a huge change in the complex impedance upon the application of a static external magnetic field. The samples were prepared by RF magnetron sputtering and their GMI behaviour was analysed experimentally as well as theoretically. In the theoretical analysis a model for the composite wire impedance was developed by solving Maxwell's equations to obtain the field distribution in every layer and by linearising the Landau-Lifschitz-Gilbert equation in order to establish an expression for the permeability tensor in the ferromagnetic shell. The dependency of the impedance on the applied field strength and the driving current frequency was measured and the experimental results were compared with the theoretical model.