Jena 2013 – scientific programme

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K: Fachverband Kurzzeitphysik

K 1: Optische Methoden und Verfahren

K 1.3: Talk

Monday, February 25, 2013, 14:45–15:00, HS 4

Time-resolved measurements of magnetization precession in different exchange bias systems — •Andrea Ehrmann¹ and Tomasz Blachowicz² — ¹Hochschule Niederrhein, Faculty of Textile and Clothing Technology, Mönchengladbach, Germany — ²Institute of Physics, Silesian University of Technology, Gliwice, Poland

Due to the large technological relevance, magnetization reversal processes in exchange bias systems are of great interest in recent research projects. In time-resolved measurements, the change of the anisotropy field (by a laser pulse, a field pulse etc.) leads to a precession of the magnetic moments in the sample. Angle-resolved measurements of the precession frequencies, e.g. by MOKE (Magneto-Optic Kerr-Effect) give rise to the sample's anisotropies. These experiments are significantly faster than common BLS (Brillouin Light Spectroscopie) measurements, thus allowing for a large number of detection angles.

In this way, different anisotropies in the exchange bias systems Fe/MnF2 and Fe/FeF2 can be detected. Additional to the form anisotropy, the interface anisotropy, and the magneto-crystalline anisotropy, the exchange bias anisotropy can be depicted. Our measurements show that in both systems under examination, a new mathematical model for the exchange bias has to be found, which leads to the assumption that accurate time-resolved measurements on other material systems can also give rise to novel theoretical descriptions of the exchange bias anisotropy.

[1] A. Tillmanns: Magnetisierungsumkehr und -dynamik in Exchange-Bias-Systemen, Dissertation, RWTH Aachen 2006