Demagnetization effects on magnetization, susceptibility, and ESR in spin-glasses

Abstract

For ellipsoidal samples of spin-glass, with one of the principal axes collinear to the static field and the cooling field, the magnetization, susceptibility, and ESR frequencies are derived. Both longitudinal and transverse modes are affected, but the shifts become as large as 1% only for 10 at.% concentrations of magnetic impurity (e.g., Mn in $\mathrm{CU}\mathrm{Mn}$). The shifts display a considerable dependence on the sample shape and the orientation of the applied field. The magnetization and susceptibility are decreased by the same factor, slightly greater than unity. Level repulsion effects can occur, depending on the material parameters and demagnetization geometry.