Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 50: Poster II

MA 50.17: Poster

Friday, March 15, 2013, 10:30–13:30, Poster D

Domain formation in laminated FeCoBSi films for ME sensor applications — •Necdet Onur Urs¹, Christine Kirchhof¹, Dirk Meyners¹, Robert Jahns², Eckhard Quandt¹, Reinhard Knöchel², and Jeffrey McCord¹ — ¹Institute for Materials Science, Kiel University, Germany — ²Institute of Electrical and Information Engineering, Kiel University, Germany

Magnetic domain activities in magnetoelectric (ME) sensors severely limit the sensor sensitivity, which can be solved by laminating the magnetic layers with non-magnetic materials. Magnetron-sputtered FeCoBSi/Ta multilayer thin films of different thicknesses and their single layer counterparts with the same total thickness are investigated by magneto-optical Kerr microscopy. All samples are annealed under a magnetic field to obtain a well defined uniaxial anisotropy. The domain structure changes depending on the FeCoBSi layer thickness [1]. The coupling between the domains of the adjacent magnetic layers through magneto-static interaction causes the domain walls to align themselves to their peers in the neighboring layers eliminating the magnetic charges from the interior of the films [1]. Magnetic hysteresis loops show a significant drop in coercivity [2]. In patterned samples, the magnetic closure domains display a transition from a modified spike domain to a closure domain structure and the domain rotation starts to become dominant in the magnetization reversal process. As a result Barkhausen noise in ME-sensors is reduced considerably. [1] J. C. Slonczewski, B. Petek, B. E. Argyle, IEEE Transactions on Magnetics (1988) [2] J. McCord and J. Westwood, J. Appl. Phys. 87, 6592 (2000)