Magnetic ordering above room temperature in the sigma-phase of Fe66V34

Magnetic properties of four sigma-phase Fe100−xVx samples with 34.4⩽x⩽55.1 were investigated by Mössbauer spectroscopy and magnetic measurements in the temperature interval 4.2–300 K. Four magnetic quantities, viz. hyperfine field, Curie temperature, magnetic moment and susceptibility, were determined. The sample containing 34.4 at% V was revealed to exhibit the largest values found up to now for the sigma-phase for average hyperfine field, 〈B〉=12.1 T, average magnetic moment per Fe atom, 〈μ〉=0.89 μB, and Curie temperature, TC=315.3 K. The quantities were shown to be strongly correlated with each other. In particular, TC is linearly correlated with 〈μ〉 with a slope of 406.5 K/μB, as well as 〈B〉 is so correlated with 〈μ〉, yielding 14.3 T/μB for the hyperfine coupling constant.