Parallel Pumping of Magnetoelastic Waves in Lithium Ferrite

The parallel pumping technique is used to measure the magnetoelastic properties of single-crystal lithium ferrite at room temperature. This technique is extended to cover measurements of the magnetoelastic coupling constant B₁. Measurements of the exchange constant, spin-wave linewidth, and elastic Q at 17.3 Gc/sec are also presented. Molecular-field theory predicts an exchange constant for lithium ferrite which is half the experimental value. The three-magnon relaxation process accounts for only part of the k dependence of the spin-wave losses. The elastic Q for lithium ferrite at this frequency is approximately half that for yttrium iron garnet.