Abstract
We observe that an rf microwave field strongly influences the transport of incoherent thermal magnons in yttrium iron garnet. Ferromagnetic resonance in the nonlinear regime suppresses thermal magnon transport by 95%. The transport is also modulated at nonresonant conditions in two cases, both related to the magnon band minimum. Firstly, a strong enhancement of the nonlocal signal appears at a static magnetic field below the resonance condition. This increase only occurs at one field polarity and can be as large as 800%. We attribute this effect to magnon kinetic processes, which give rise to band-minimum magnons and high-energy chiral surface modes. Secondly, the signal increases at a static field above the resonance condition, where the rf frequency coincides with the magnon band minimum. Our study gives insight into the interplay between coherent and incoherent spin dynamics: the rf field modifies the occupation of relevant magnon states and, via kinetic processes, the magnon spin transport.
| Original language | English |
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| Article number | 054420 |
| Journal | Physical Review B |
| Volume | 99 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 19 Feb 2019 |
Funding
We appreciate G. E. W. Bauer for suggestions and we thank T. Kuschel, T. van der Sar, P. S. Haughian, M. Weiler, A. Kamra, J. Shan, K. Oyanagi, and M. Schabes for discussions. We acknowledge H. M. de Roosz, J. G. Holstein, H. Adema, and T. J. Schouten for their technical assistance. This work is part of the research program Magnon Spintronics (MSP) No. 159 financed by the Netherlands Organisation for Scientific Research (NWO). We appreciate support from the NanoLab NL and the Zernike Institute for Advanced Materials. This research is partly financed by the NWO Spinoza prize awarded to Prof. B. J. van Wees. Further support by EU FP7 ICT Grant No. 612759 InSpin and Marie Curie initial training network Spinograph (607904) is gratefully acknowledged.