Regensburg 2016 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 48: Poster Session II
MA 48.23: Poster
Donnerstag, 10. März 2016, 15:00–18:00, Poster B1
Resonant optical excitation of ultrafast magnetization dynamics in Iron Garnets by a sequence of optical pulses — •Manuel Jäckl1, Dmitri Morosov1, Igor V. Savochkin2, Dmitri V. Dodonov3, Ilya A. Akimov1,4, Vladimir I. Belotelov4,5, Anatoly K. Zvezdin3,5, and Manfred Bayer1,4 — 1Experimentelle Physik 2, TU Dortmund, D-44221 Dortmund, Germany — 2Lomonosov Moscow State University, 119991 Moscow, Russia — 3Moscow Institute of Physics and Technology, Moscow Region, 141700 Russia — 4A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia — 5Russian Quantum Center, Skolkovo, Moscow Region, 143025 Russia
We use the inverse Faraday effect in order to influence the magnetization of a ferromagnetic bismuth iron garnet (BIG) films by means of circularly polarized femtosecond laser pulses, leading to a precession of the magnetization with a lifetime of several nanoseconds and a frequency between 2 – 7 GHz in transverse magnetic fields of 70 – 250 mT, respectively. Using a sequence of optical pulses with a repetition rate of FRep=1 GHz which is larger than the decay rate of the oscillation, allows us to achieve synchronization of spin wave modes with frequencies F which satisfy the resonance condition of F=n FRep (n is an integer). Consequently the amplitude of the magnetization precession increases when the modes are synchronized. Fourier sum analysis of the data and its magnetic field dependence allow to evaluate the comprehensive spectrum of spin waves in studied samples.