Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 33: Spin-Dynamics, Magnetization Reversal III
MA 33.5: Vortrag
Donnerstag, 30. März 2006, 16:15–16:30, HSZ 403
Nanosecond magnetization dynamics with pulsed high fields in microcoils — •Martin Weisheit1,2, Marlio Bonfim1, Vitoria Barthem1, Sebastian Fähler2, and Dominique Givord1 — 1Laboratoire Louis Neél, CNRS Grenoble, 25 av. des Martyrs, F-38042 Grenoble Cedex 9, France — 2Institute for Metallic Materials, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany
In order to study the switching of highly anisotropic magnetic materials, which can have coercivities of a few T, pulsed magnetic fields may be employed. Very high fields of up to 50 T can be generated by short current pulses in microcoils [1]. Coils with inner diameters of 50 µ m are used, for which pulse energies below 1 J are sufficient, allowing for very compact and fast designs. Since field rise times are of the order of 1 T/ns, the dynamics of magnetization behavior become apparent. This is demonstrated by polar Kerr effect measurements on FePt thin films, where the observed coercivity is drastically increased compared to Hc, static=5.6 T as measured by VSM [2]. Simulations of the magnetization response to the external field pulse, using a no-precession approximation of the Landau-Lifshitz-Gilbert equation, compare well with the pulsed field measurements.
[1] M. Bonfim, K. Mackay, S. Pizzini, M.-L. Arnou, A. Fontaine, G. Ghiringhelli, S. Pascarelli, and T. Neisius, J. Appl. Phys. 87 (2000) 5974
[2] M. Weisheit, L. Schultz, and S. Fähler, J. Appl. Phys. 95 (2004) 7489