Peculiar effect of rare earth doping on magnetic and magnetocaloric properties in Fe-rich amorphous ribbons

We report the influence of rare-earth doping on magnetic and magnetocaloric properties of Fe82RE4B4Mn4Zr4Nb2 (RE = La, Ce, Pr, Nd, Gd) ribbons prepared by melt-spinning method. The amorphous structure of the ribbons has been examined by X-ray diffraction technique. Temperature dependence of the magnetization shows that the Curie temperature is changeable in the RE-doped ribbons. Differential scanning calorimetry measurements indicate that the ribbons exhibit excellent thermal stability at room temperature. The ribbons show large magnetocaloric effect in a broad temperature range. Taking a temperature span of 60 K, the values of refrigeration capacity with a field change of 3 T are found to be 119, 87, 120, 115, 81 J/kg for RE = La, Ce, Pr, Nd, Gd, respectively. Universal behavior is observed in the isothermal entropy change curves for each sample with different field changes, and the curves for all the samples with the same field change.