Relaxation in a spin glass system with competing magnetic interactions: Fe_0.16Cr_0.84

The authors present magnetic relaxation measurements in the spin glass Fe_0.16Cr_0.84 as a function of temperature (1.5K<or=T<or=7.5K) and magnetic field (100 Oe<or=H<or=3 kOe). The relaxation rate is described by a power law where the exponent a depends on temperature and field. They find that all a(H,T) collapse to a single curve when plotted as a function of H/H_s, where H_s is a temperature-dependent scaling parameter. This curve can be extrapolated to give a=0 at a critical field H_c(T) which they identify as the de Almeida-Thouless line.