THE EFFECT OF TWO-MAGNON SCATTERING ON PARALLEL-PUMP INSTABILITY THRESHOLDS.
HARVARD UNIV CAMBRIDGE MASS DIV OF ENGINEERING AND APPLIED PHYSICS
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Following a general description of the important properties and symmetries of the parallel-pump coupling and of two-magnon scattering, several theoretical approaches to the problem of the effect of two-magnon scattering on the parallel-pump instability threshold are explored. A successful approach, based on the rate of energy flow among the spinwave modes and involving only elementary mathematical tools, is developed. Extensive experimental data on the wave vector dependence of delta H sub k over a wide range of temperatures in ferromagnetic CdCr2Se4 are also presented. Results of theoretical calculations at several temperatures are compared with these data, and interesting information about spinwave renormalization and the dominant multimagnon scattering mechanisms at temperatures up to about 90 of the Curie temperature is obtained. Author
- Solid State Physics