Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)

MA 20.79: Poster

Dienstag, 28. März 2006, 15:15–19:15, P1

Influence of surface roughness to the decay of precessional magnetization motion — •Bjoern Becker, Tobias Martin, Matthias Sperl, Philipp Kotissek, and Guenther Bayreuther — Institut fuer Experimentelle und Angewandte Physik, Universitaet Regensburg, Regensburg, Germany

A non-exponential decay of the uniform precessional motion of the magnetization in ferromagnetic films according to exp(−|t/τ|^3/2) has been predicted recently [1]. The decay time τ should be related to the surface roughness [1]. In the present study an attempt was made to test the prediction of such a correlation. Epitaxial Fe films were grown by MBE on clean GaAs(110) wafers and on GaAs(110) surfaces prepared by cleaving in ultra high vacuum. The cleaved edges are atomically flat with terrace widths up to 2 µm x 2 µm as shown by STM. The roughness of the upper surface of the Fe films was altered by variation of the growth temperature. Magnetic anisotropies were determined by MOKE. A pulsed inductive microwave magnetometer (PIMM) was used to measure the frequency, the amplitude and the decay time of the precession following a short field pulse. Intrinsic and extrinsic contributions to the observed decay time are discussed as well as the effect of structural defects and interface roughness.

[1] A. Dobin, Phys. Rev. Lett. 92, 257204 (2004)