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 TC≈170K, while the spin-freezing temperature was ∼164K. Its relative shift per decade of ac frequency was 0.002, a value smaller than that typical of canonical spin-glasses. Magnetic entropy change, ΔS, in the vicinity of TC was determined for magnetic field, H, ranging between 5 and 50kOe. Analysis of ΔS in terms of the power law yielded the critical exponent, n, vs. temperature with the minimum value of 0.75 at TC, while from the analysis of a relative shift of the maximum value of ΔS with the field a critical exponent Δ=1.7 was obtained. Based on scaling laws relationships values of other two exponents viz. β=0.6 and γ=1 were determined.