Parametric excitation of spin waves in strongly anisotropic uniaxial ferrites

The thresholds of parametric spin-wave excitation are measured in a Ba2Zn2Fe12O22 easy-plane ferrite at a pumping frequency of 36 GHz in the temperature range from 5 to 350 K at different angles between the external dc magnetic field and the anisotropy axis, where the pumping is, in a general case, oblique. The dependences of the spin-wave damping parameter on wave number, temperature, and the angle between the spin-wave propagation direction and the anisotropy axis have been found. The results of measuring the ferromagnetic resonance parameters in this ferrite and an easy-axis Ba(Fe0.95Sc0.05)(12)O-19 ferrite are presented. Conclusions on the relaxation processes in strongly anisotropic hexagonal ferrites are made. (C) 1999 American Institute of Physics. [S1063-7834(99)02509-5].