Magnetic properties of the spin glass Pd1-yFeyHx: hyperfine and susceptibility studies in a magnetic field

Abstract

Mossbauer hyperfine and magnetometer measurements have been made on different compositions of the spin-glass system Pd1-yFeyHx. It is found that in the spin-glass phase the hyperfine field HHF below the ordering temperature T0 shows a distribution P(HHF) which is zero for HHF less than a lower critical limit HHF0. Satisfactory numerical agreement is found with the calculations of Palmer and Pond (1979) and of Sommers (1978, 1979) for the equivalent limiting molecular field. The effect of a magnetic field on the spin orientation (T T0, strong relaxation effects have been discovered in the Mossbauer spectra in the presence of an external magnetic field. Macroscopic susceptibility and magnetisation measurements have been used to verify the presence of ferromagnetic clusters. One result is that for T>T0, the effective Curie-Weiss temperature value strongly depends on external field, caused by the very wide spectrum of interactions in a spin glass.