MAGNETIC-FIELD DEPENDENCES OF THE CHARACTERISTIC TEMPERATURES IN THE REENTRANT SPIN-GLASSES (FE0.65NI0.35)1-XMNX

The alloy system (Fe0.65Ni0.35)(1-x)Mn(x) shows reentrant spin glass behaviour for 0.04 less-than-or-equal-to x less-than-or-equal-to 0.16. In this concentration range three characteristic temperatures can be observed: the Curie-temperature T(C), the temperature which corresponds to the maximum of the spontaneous magnetisation T(m) and the third one which is in connection with the onset of strong irreversibility and the transition to a complete disordered spin glass state T(im). All these characteristic temperatures are dependent on the external magnetic field which normally is applied to measure the magnetization versus temperature. In this paper we present these dependencies which we investigated using a Faraday balance in order to measure the magnetization. Only approaching the experimentally determined triple point we observe a linear dependence of T(m) versus the external magnetic field. This is in agreement with the theoretical predictions by Dubiel et al. Therefore our discussion is based upon the contents of the work of Dubiel, Fischer, Sauer and Zinn.