Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 43: Magnetization / Demagnetization Dynamics III
MA 43.5: Vortrag
Donnerstag, 19. März 2015, 10:30–10:45, EB 301
Optically Induced Ferromagnetic Resonance in Magnetic Iron Garnets — •Manuel Jäckl1, Ilya A. Akimov1, Vladimir I. Belotelov2,3,4, Anatoly K. Zvezdin3,4, and Manfred Bayer1 — 1Experimentelle Physik 2, TU Dortmund, D-44221 Dortmund, Germany — 2Lomonosov Moscow State University, 119991 Moscow, Russia — 3Russian Quantum Center, Novaya St. 100, Skolkovo, Moscow Region, 143025, Russia — 4Prokhorov General Physics Institute, Russian Academy of Sciences, 119991 Moscow, Russia
We use the inverse Faraday effect in order to influence the magnetization of a ferromagnetic bismuth iron garnet (BIG) film by means of circularly polarized femtosecond laser pulses. Optical excitation modifies the magnetization and triggers its precession around the equilibrium position with a lifetime of several nanoseconds and a frequency of 2 – 7 GHz in transverse magnetic fields of 70 – 250 mT, respectively. The phase of the precession changes by 180 degrees when the helicity of the exciting laser pulses is switched from σ+ to σ−. Optically induced ferromagnetic resonance is achieved using a sequence of optical pulses with low pulse energy of 50 pJ and high repetition rate of FRep = 1 GHz which is larger than the decay rate of the oscillation. We observe an amplification of the laser induced Faraday rotation signal by 60 % when the precession frequency corresponds to the resonance condition (F =n FRep, n is integer).