Abstract
Using spin currents generated by fs laser pulses, we demonstrate excitation of GHz ferromagnetic resonance and THz ferrimagnetic exchange resonances in Co/Gd/Co/Gd multilayers by time-resolved magneto-optic Kerr effect measurements. Varying the Gd layer thickness allows for a tuning of the resonance spectrum by manipulating the total angular momentum and strength of effective exchange fields between the antiferromagnetically coupled layers. Close to the compensation point of angular momentum, a minimum in the frequency of the exchange-dominated mode and a maximum in the frequency of the ferromagnetic resonance mode is observed. Finally, to gain better understanding of the excitation mechanism, we analyze the anomalous variation in the measured exchange mode amplitude as a function of its frequency. A peak in this amplitude in the vicinity of the compensation point of angular momentum is explained using a macrospin model, taking nonlinear effects at finite precession amplitudes into account.
Original language | English |
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Article number | 024401 |
Number of pages | 9 |
Journal | Physical Review B |
Volume | 108 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Jul 2023 |
Funding
This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie Grant Agreement No. 861300. This work is part of the Gravitation programme “Research Center for Integrated Nanophotonics”, which is financed by the Netherlands Organization for Scientific Research (NWO).
Funders | Funder number |
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Marie Skłodowska‐Curie | 861300 |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek | |
European Union's Horizon 2020 - Research and Innovation Framework Programme |