Magnetism of a sigma-phase Fe60V40 alloy: magnetic susceptibilities and magnetocaloric effect studies

Abstract

Magnetic properties of a sigma-phase Fe60V40 intermetallic compound were studied by means of ac and dc magnetic susceptibility and magnetocaloric effect measurements. The compound is a soft magnet yet it was found to behave like a re-entrant spin-glass system. The magnetic ordering temperature was found to be T_C ca.170 K, while the spin-freezing temperature was ca.164 K. Its relative shift per decade of ac frequency was 0.002, a value smaller than that typical of canonical spin-glasses. Magnetic entropy change, DeltaS, in the vicinity of T_C was determined for magnetic field, H, ranging between 5 and 50 kOe. Analysis of DeltaS in terms of the power law yielded the critical exponent, n, vs. temperature with the minimum value of 0.75 at T_C, while from the analysis of a relative shift of the maximum value of DeltaS with the field a critical exponent Delta=1.7 was obtained. Based on scaling laws relationships values of other two exponents viz. betha=0.6 and gamma=1 were determined.