Structural, magnetic and magnetocaloric performances in Cu18Al25Ho57 and Cu18Al25Tm57 amorphous ribbons

The rapidly solidified Cu(18)Al(25)Ho(57 )and Cu18Al25Tm57 melt-spun ribbons have been successfully synthesized. Both ribbons show complete amorphous characteristics based on the analysis of the X-ray diffraction (XRD) and differential scanning calorimeter (DSC). Magnetic measurements illustrate that a paramagnetic to ferromagnetic type transition takes place at Curie temperatures T-C of 22.2 and 4.9 K for Cu(18)Al(25)Ho(57 )and Cu18Al25Tm57, respectively, which are companied with a considerable magnetocaloric effect (MCE). For a magnetic field change (Delta H) of 0-7 T, Cu18Al25Ho57 and Cu18Al25Tm57 ribbons display the maximum magnetic entropy (Delta S-M(max)) of 24.8 and 20.9 J kg(-1) K-1, the refrigerant capacity (RC) determined from the area below a full-width at half-maximum (delta T-FWHM) for Delta S (T)curve of 582.9 and 385 J kg(-1), respectively. The large MCEs at low temperatures demonstrate that Cu18Al25RE57 (RE = Ho and Tm) are competitive candidates among the MCE materials working at liquid hydrogen and liquid helium temperature zones.