Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 33: Poster II
MA 33.74: Poster
Friday, March 26, 2010, 11:00–14:00, Poster B1
Spin-wave quantization in a thermal well — •Sebastian Schäfer, Helmut Schultheiss, and Burkard Hillebrands — FB Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern, 67663 Kaiserslautern, Germany
We report on micromagnetic simulations of two-dimensional spin-wave quantization caused by a local reduction of the saturation magnetization MS, using the OOMMF code [1]. This reduction models the effect of a heat gradient in a 10 nm thin Permalloy film as could be caused by nanometer-sized point contacts with high current densities as well as a focused laser beam of high intensity. It is therefore called thermal well. We found high-intensity spin-wave excitations confined to the area of the thermal well. Those modes exhibit frequencies distinctively different from the spin-wave band of the thin Permalloy film. The quantization effects apparently are not – as in previous investigations [2] – governed by the geometrical confinement or demagnetization fields but only by the modified saturation magnetization. The nature of these modes as well as the dependence on the depth and width of the thermal well will be discussed.
[1] M. J. Donahue, and D. G. Porter, Report NISTIR 6376, National Institute of Standards and Technology, Gaithersburg, MD (1999).
[2] J. Jorzick, S.O. Demokritov, B. Hillebrands, M. Bailleul, C. Fermon, K.Y. Guslienko, A.N. Slavin, D.V. Berkov, N.L. Gorn, Phys. Rev. Lett. 88, 047204 (2002).