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

A magnetocaloric effect with wide tunability was observed in melt-spun amorphous Gd65Fe15-xCo5+xAl10Si5 (x = 0, 5, 10) alloys of different Fe/Co ratios. Their magnetic properties were compared with those of the previously investigated parent alloy Gd65Fe10Co10Al15. The glassy structure of the melt-spun samples was confirmed by X-ray diffraction (XRD) and Fe-57 Mossbauer 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 Delta S-M = - 6.8 J/kg K was obtained for Gd65Fe5Co15Al10Si5, 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 (Delta S-M proportional to H-n). [GRAPHICS]

Automated summary

A magnetocaloric effect with wide tunability was observed in melt-spun amorphous Gd65Fe15-xCo5+xAl10Si5 alloys of different Fe/Co ratios. The Curie temperatures of the samples were between 155 and 195 K and increased with decreasing Co content. The highest magnetic entropy change ΔS-M was obtained for Gd65Fe5Co15Al10Si5 when the magnetic field was increased from 0 to 5 T.