Magnetocaloric effect in amorphous and partially crystallized Fe₈₀Zr₇Cr₆Nb₂Cu₁B₄ alloy

In the present work the microstructure and thermomagnetic properties of Fe₈₀Zr₇Cr₆Nb₂Cu₁B₄ ribbon in the as-quenched state and after the accumulative annealing in the temperature range 600-800 K for 10 min were studied using Mössbauer spectroscopy and vibrating sample magnetometry. The second order phase transition from ferro- to paramagnetic state is observed. The Curie temperature T_{C} defined as inflection point on the magnetization versus temperature curve recorded on zero-field cooled mode equals 262.5 K for the as-quenched material. With increasing the annealing temperature increase of T_{C} is observed. The maximum value of the magnetic entropy change (-ΔS) observed in the vicinity of the Curie point is equal to 0.85 J/(kg K) for the alloy in the as-quenched state. Moreover, for the samples annealed up to 750 K for 10 min the low intensity maximum at about 190 K related to the supplementary magnetic phase is observed. The presence of this phase was confirmed as additional component visible on hyperfine field distributions of Mössbauer spectra