Anregung und Kontrolle von Spinwellen in ferromagnetischen Strukturen durch fs-Laserpulse
Zusammenfassung der Projektergebnisse
Spin waves or magnons – the elementary excitations of magnetic moments localized periodically in a crystal lattice – are considered to be promising for high speed information processing and its transport in electronic circuits. The generation of spin waves by femtosecond laser pulses and their time-dynamics provides several important advances with respect to conventional approaches using microwaves. We investigated and developed optical methods for efficient and tunable spin wave generation in magnetic dielectric structures, where the inverse Faraday effect can be efficiently exploited for non-thermal control of magnetization within the laser excitation spot in combination with small Gilbert damping. Applying a pulse sequence with high repetition rate of ultimately up to 10 GHz in combination with high spatial resolution we have obtained the following results. 1) Manifestation of optically driven ferromagnetic resonance (OD-FMR) at 10 GHz and demonstration of high tunability of spin wave directionality from unidirectional to X-shaped caustic pattern, which is obtained by means of detuning of the FMR frequency with respect to the pulse repetition rate; 2) Excitation of spin waves in confined magnetic structures, where the spin wave confinement leads to appearance of new resonances in optically induced FMR spectra and allows switching between bulk and surface waves by small magnetic field variation; 3) In addition to magnetization dynamics in ferrimagnetic iron garnets we have demonstrated selective excitation of trion magnetic polarons and optical readout of hole magnetic polaron in diluted magnetic semiconductor quantum wells; 4) Finally, we revealed significant role of random effective magnetic fields for spin dynamics of resident electrons in hybrid MoSe2/EuS heterostructures using single beam technique with high repetition rate of 1 GHz. The obtained results contribute to the development of optical spin wave injection in magnetic dielectric and semiconductor structures and initiate realization of novel photonic and optoelectronic circuits and sensors.
Projektbezogene Publikationen (Auswahl)
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Accumulation and control of spin waves in magnonic dielectric microresonators by a comb of ultrashort laser pulses. Scientific Reports, 12(1).
Khramova, A. E.; Kobecki, M.; Akimov, I. A.; Savochkin, I. V.; Kozhaev, M. A.; Shaposhnikov, A. N.; Berzhansky, V. N.; Zvezdin, A. K.; Bayer, M. & Belotelov, V. I.
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Trion magnetic polarons in (Cd,Mn)Te/(Cd,Mn,Mg)Te quantum wells. Physical Review B, 106(19).
Godejohann, F.; Akhmadullin, R. R.; Kavokin, K. V.; Yakovlev, D. R.; Akimov, I. A.; Namozov, B. R.; Kusrayev, Yu. G.; Karczewski, G.; Wojtowicz, T. & Bayer, M.
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Tuning the directionality of spin waves generated by femtosecond laser pulses in a garnet film by optically driven ferromagnetic resonance. Physical Review B, 107(6).
Khramova, A. E.; Kobecki, M.; Akimov, I. A.; Savochkin, I. V.; Kozhaev, M. A.; Shaposhnikov, A. N.; Berzhansky, V. N.; Zvezdin, A. K.; Bayer, M. & Belotelov, V. I.
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Spin relaxation of localized electrons in monolayer MoSe2 : Importance of random effective magnetic fields. Physical Review B, 110(16).
Yalcin, Eyüp; Kalitukha, Ina V.; Akimov, Ilya A.; Korenev, Vladimir L.; Ken, Olga S.; Puebla, Jorge; Otani, Yoshichika; Hutchings, Oscar M.; Gillard, Daniel J.; Tartakovskii, Alexander I. & Bayer, Manfred
