Effect of irradiation on magnetic properties of Fe-Ni alloys

Abstract

Hysteresis loop measurements were conducted on several commercial iron-nickel alloys during neutron irradiations at 90°K and at temperatures up to 175°C, in both zero and saturating magnetic fields. Isochronal annealing tests were also performed on the alloys after irradiation. The low-temperature irradiation results indicated that magnetic properties are affected not by the point defects themselves but by their motion and eventual disposition. The radiation-induced changes appeared similar in many ways to those observed in these alloys upon magnetic annealing. Experiments on the alloys at temperatures from 70°to 175°C in a saturating magnetic field showed that the activation energy of the radiation-induced process was 0.3 eV. In all cases the radiation-induced changes were annealed out at temperatures below the usual ordering temperature for Ni3Fe. This recovery process appeared to be dependent upon the state of the magnetization of the sample. © 1964 The American Institute of Physics.