Hamburg 2001 – wissenschaftliches Programm

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SYDU: Dynamik von Ummagnetisierungsvorgängen

SYDU III: HV III

SYDU III.1: Hauptvortrag

Donnerstag, 29. März 2001, 10:30–11:00, S5.2

Laser control of ferro- and antiferromagnetism — •Wolfgang Hübner¹, Guoping Zhang², and Mikolaj Trzeciecki¹ — ¹Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle — ²Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996-1200

Conventional magnetization dynamics, such as precession, coherent rotation as well as domain-wall motion, occurs on the nanosecond time scale and results from spin-lattice, magnetic dipole and Zeeman, and spin-spin interactions. By contrast, recent observations of magnetic subpicosecond dynamics rely on different mechanisms:
(i) Dephasing of quantum states occurs within 10 to 20 fs and has a magnetic contribution that can be observed in linear as well as nonlinear pump-probe experiments in both ferro-[1] and antiferromagnets.
(ii) Demagnetization and spin manipulation by magnetic population dynamics results from the combined action of the laser pump field and spin-orbit coupling within times that can be as short as 20 to 80 femtoseconds[2].
We discuss these two theoretical predictions for Ni and NiO as well as their possible experimental verification.

W. Hübner and G. P. Zhang, Phys. Rev. B 58, R5920-R5923 (1998).
G. P. Zhang and W. Hübner, Phys. Rev. Lett. 85, 3025-3028 (2000).