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MA: Fachverband Magnetismus

MA 35: Spin-Dynamics / Spin-Torque IV

MA 35.14: Vortrag

Donnerstag, 26. März 2009, 18:45–19:00, HSZ 04

Three-dimensional control of the antiferromagnetic order parameter in nickel oxide — •Andrea Rubano¹, Takuya Satoh², and Manfred Fiebig¹ — ¹HISKP, University of Bonn, Germany — ²Institute of Industrial Science, University of Tokyo, Japan

A three-dimensional switching of the antiferromagnetic (AFM) order parameter has been achieved in the exchange-bias compound NiO by means of an intense optical excitation. By controlling the power and pulse length of the pump pulse the AFM order parameter was transiently oriented into the easy(1) axis, the easy(2) axis, or the hard axis direction. The reorientation was evidenced by optical second harmonic generation beating processes. The relation between the pump-pulse parameters and the induced direction of the AFM order parameter was investigated in detail. At constant pump-pulse energy we tuned its temporal duration: “short pulse” (≈ 110 fs) switch the AFM order parameter into the hard axis direction, while longer pulses (≈ 130 fs) set the order parameter along the easy(2) axis. We ascribe the observed phenomenon to the competition between “hot carrier” creation modifying the magnetic anisotropy and electron-electron relaxation processes occurring on the same timescale.