Temperature variation of ferromagnetic relaxation in the3dtransition metals

We report measurements on the ferromagnetic resonance in single-crystal specimens of hcp Co, Ni, and Fe. The linewidth data have been analyzed to obtain the temperature dependence of the ferromagnetic relaxation frequency $\lambda$. These temperature dependences can be qualitatively understood in terms of recent theories. On the other hand, it turns out that in some cases $\lambda$ is essentially constant over wide ranges of temperature. This behavior is unexplained at present.