Large magnetocaloric effect and critical parameters around room temperature in the Fe₇₉Cr₆B₂Nd₃Zr₁₀ alloy ribbon

Abstract

In this work, we have investigated magnetic properties, the magnetocaloric effect, and critical behavior in the Fe₇₉Cr₆B₂Nd₃Zr₁₀ amorphous alloy ribbon prepared by the melt-spinning method. This alloy undergoes a second-order ferromagnetic–paramagnetic (FM–PM) phase transition around its Curie temperature T_C ≈ 300 K. A large value of maximum entropy change, |ΔS_m|_max ≈ 1 J kg⁻¹ K⁻¹, was achieved for a magnetic field change of 12 kOe in a wide range of operative temperature. To clarify the nature of the FM–PM phase transition and magnetic interactions in the alloy, a set of critical parameters (β, γ) has been determined using two different methods. The obtained values are β = 0.486 ± 0.021, γ = 1.068 ± 0.017 by the modified Arrott plot method, while β = 0.482 ± 0.008, γ = 1.060 ± 0.024 by the Kouvel–Fisher method. These values are close together and to those expected from the mean-field model, which reveals a long-range FM interaction in this alloy.