Tunable magnetocaloric effect in amorphous Gd-Fe-Co-Al-Si alloys

Abstract A magnetocaloric effect with wide tunability was observed in melt-spun amorphous Gd 65 Fe 15-x Co 5+x Al 10 Si 5 ( x = 0, 5, 10) alloys of different Fe/Co ratios. Their magnetic properties were compared with those of the previously investigated parent alloy Gd 65 Fe 10 Co 10 Al 15 . The glassy structure of the melt-spun samples was confirmed by X-ray diffraction (XRD) and 57 Fe Mössbauer spectrometry. Their Curie temperatures ( T C ) were between 155 and 195 K and increased significantly with decreasing Co content. The highest value of the magnetic entropy change Δ S M = − 6.8 J/kg K was obtained for Gd 65 Fe 5 Co 15 Al 10 Si 5 , when the magnetic field was increased from 0 to 5 T. Refrigerant capacity (RC) takes values close to 700 J/kg for the whole series of the alloys. The occurrence of the second-order phase transition and the conformity of the magnetic behavior with the mean field model were concluded on the basis of the analysis of the universal curves and the values of the exponent n (Δ S M ∝ H n ). Graphical abstract