| Autor: |
Bauer, Hans G., Majchrak, Peter, Kachel, Torsten, Back, Christian H., Woltersdorf, Georg |
| Rok vydání: |
2014 |
| Předmět: |
|
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1038/ncomms9274 |
| Popis: |
Non-linear magnetization dynamics is essential for the operation of many spintronics devices. For microwave assisted switching of magnetic elements the low field regime is of particular interest. In addition a large number of experiments uses high amplitude FMR in order to generate d.c. currents via spin pumping mechanism. Here we use time resolved X-ray magnetic circular dichroism experiments to determine the number density of excited magnons in magnetically soft Ni_80Fe_20 thin films at small bias fields and large rf-excitation amplitudes. Our data shows that the common model of non-linear ferromagnetic resonance is not suitable to describe the low bias field limit. Here we derive a new model of parametric spin-wave excitation which correctly predicts threshold amplitudes and decay rates also at low bias fields. In fact a new series of critical modes with amplitude phase oscillations is found, generalizing the theory of parametric spin-wave excitation. |
| Databáze: |
arXiv |
| Externí odkaz: |
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