Critical behaviour of the electrical resistivity in amorphous ferromagnetic alloys

Abstract

Electrical resistivity ρ of the amorphous Fe_xNi_80-xB₁₉Si₁ (χ = 10, 13, 16), Fe₂₀Ni₆₀B₂₀ and Fe₂₀Ni₆₀P₁₄B₆ alloys has been measured in a wide temperature range which embraces the second-order magnetic phase transition at the Curie point T_C. Analysis of the data reveals that in these systems critical region has a much wider range compared with that in crystalline ferromagnets even though dρ/dT for T≥T_C decreases at a rate that is comparable in both the cases. For the glassy ribbons coming from the same alloy batch, T_C and the specific heat critical exponent a have the same values as those determined from our previous magnetic measurements. a for all the investigated alloys possesses values that are typical of a Heisenberg ferromagnet.