Pressure dependence of the irradiation-induced ferromagnetism in FeNi invar alloys

Pressure dependence of the irradiation-induced ferromagnetism recently found in FeNi invar alloys was investigated under hydrostatic pressures up to 7.5 GPa. A rectangular sheet of Fe-30.2 at% Ni invar alloy was irradiated with 80 MeV Xe ions. The range was much smaller than the thickness of the sample. The Curie temperature of the irradiated part increased by 63 K, and the absolute value of the pressure coefficient, d Tc/dp was smaller than that of non-irradiated part. The relation p ~ (T co T c)n holds with n = 2 for both non-irradiated and irradiated part. The itinerant character was not so much modified by irradiation.