Abstract
In magnetic materials, the exchange is the strongest quantum interaction due to the Pauli exclusion principle. For that reason it can induce high-frequency modes of the magnetization precession. In this work we investigate these modes over a wide range of temperatures () and magnetic fields up to in a bismuth-doped garnet with perpendicular magnetic anisotropy by performing femtosecond magneto-optical pump-probe experiments. Near the compensation temperature the divergence of allows identifying unambiguously with the rare-earth iron exchange mode. In addition, at low temperature is independent of the field as usually observed. In contrast, we find that near decreases linearly with an increasing magnetic field. This behavior is explained in the context of the ferromagnetic resonance theory by including the perturbation term linear in the external applied field .
- Received 6 May 2016
DOI:https://doi.org/10.1103/PhysRevB.94.054422
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