MAGNONS IN SPIN-GLASSES - THE HIGH-FIELD LIMIT

A study is made of the high-field behavior of the linearized magnetic excitations (magnons) in spin glasses. A +/-J Heisenberg spin Hamiltonian is postulated, and the applied magnetic field is assumed to be sufficiently strong to ensure alignment of the ground state. Numerical calculations of the density of states, the localization indices, and the zero-temperature dynamic structure factor are carried out for a simple-cubic lattice with nearest-neighbor interactions and the results compared with the predictions of a self-consistent theory based on a coherent-exchange approximation. A comparison is also made with the corresponding results obtained in zero applied field.