Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Spin-Dynamics / Spin-Torque IV
MA 35.13: Vortrag
Donnerstag, 26. März 2009, 18:30–18:45, HSZ 04
Thermally assisted magnetisation switching close to the Curie temperature: elliptical and linear reversal — •Denise Hinzke1, Natalia Kazantseva2, Roy W. Chantrell2, and Ulrich Nowak1 — 1Universität Konstanz, 78457 Konstanz — 2University of York, York YO10 5DD, U. K.
Laser induced magnetic writing processes have been extensively studied recently as a possibility to improve the storage density as well as the writing speed in magnetic data storage. In our work, we focus on magnetisation reversal processes during laser heating in the presence of a magnetic field. This is important for the understanding of the dynamics of writing processes in the pico-second time scale and in relation to Heat Assisted Magnetic Recording. This technique has been proposed as a means of writing information on high anisotropy magnetic media.
We investigate the thermally assisted switching analytically within the framework of the Landau-Lifshitz-Bloch equation recently derived by D. Garanin [1]. Close to the Curie temperatures Tc two different reversal modes appear: elliptical as well as linear reversal [2]. The latter one plays a crucial role for the dynamics of the magnetisation reversal close to and especially above Tc. We have calculated the coercive fields and the energy barriers for both reversal modes as well as the minimal switching time and field needed for thermally assisted switching below and above Tc.
[1] D. A. Garanin, Phys.Rev. B 55, 3050 (1997), [2] N. Kazantseva et al, submitted for publication