AbstractA 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 57Fe Mössbauer spectrometry. Their Curie temperatures (TC) were between 155 and 195 K and increased significantly with decreasing Co content. The highest value of the magnetic entropy change ΔSM = − 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 (ΔSM ∝ Hn).
Graphical abstract
Spin-dependent magnetism and superparamagnetic contribution to the magnetocaloric effect of non-stoichiometric manganite nanoparticles