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

TL;DR

This study investigates the magnetic properties and magnetocaloric effect of a sigma-phase Fe60V40 alloy, revealing its re-entrant spin-glass behavior and critical exponents near its magnetic transition temperature.

Contribution

It provides detailed magnetic susceptibility and magnetocaloric measurements, and determines critical exponents, offering new insights into the magnetic behavior of Fe-V sigma-phase alloys.

Findings

Re-entrant spin-glass behavior observed.

Critical exponents near T_C determined.

Magnetic entropy change analyzed with power law.

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.