Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Magnetic Measurement Methods

MA 17.2: Vortrag

Dienstag, 27. März 2012, 12:00–12:15, EB 202

Determining the cone angle of magnetization via magnetoresistance measurements — •Matthias Hille, Axel Frauen, Björn Beyersdorf, André Kobs, Simon Heße, Robert Frömter, and Hans Peter Oepen — Institut für Angewandte Physik, Hamburg, Germany

Magnetic thin film systems like Co/Pt multilayers undergo a spin-reorientation transition via the canted phase [1]. In the cone state it is difficult to determine the angle of magnetization as the area-averaged value in remanence can be altered by the decomposition of the ferromagnet into domains. We present a method to accurately determine the canting angle of Co/Pt multilayers. We use the recently published Anisotropic Interface Magnetoresistance (AIMR) [2] where an increase in the magnetoresistance is observed when rotating the magnetization from the transversal in-plane to the out-of-plane direction. In our method a magnetic field is rotated in 1° steps from in-plane to perpendicular orientation. For each angle the longitudinal resistance is measured at varying field values (from 168 mT to 92 mT). In general an external field leads to a change of the direction of magnetization, except for the case that the external field is aligned parallel to the internal anisotropy field (which defines the orientation of the canting angle). In this case the resistance difference between two field values that prevent domain decay becomes zero. This allows us to determine the canting angle with an accuracy of 2°.

[1]: Frömter et al, Phys. Rev. Let. 100, 207202 (2008)

[2]: Kobs et al, Phys. Rev. Let. 106, 217207 (2010)