Quasi-archetypal spin-glass freezing at the paramagnetic-ferromagnetic boundary in re-entrant spin glasses

Abstract

The differential AC magnetoresistance and differential AC susceptibility of three amorphous FeNi re-entrant spin glasses have been examined as a function of temperature at the so-called paramagnetic-ferromagnetic transition under static magnetic fields up to 70 Oe. It is shown that the static field tends to nullify the effect of the ferromagnetic component and the results indicate the presence of spin-glass freezing in both the magnetoresistance and susceptibility which takes place simultaneously with the establishment of the ferromagnetic phase at the Curie temperature. The composite nature of the transition appears to be a general feature of re-entrant spin glasses.