The influence of Si addition on the glass forming ability, magnetic and magnetocaloric properties of the Gd-Fe-Al glassy ribbons

Abstract

The effects of Si substitution for Al on the glass forming ability, Curie temperature TC, magnetocaloric effect, and refrigeration capacity (RC) of melt-spun Gd-based Gd65Fe20Al15−xSix (x = 0–7) glassy ribbons have been investigated. The small amounts of Si substitution for Al in the Gd65Fe20Al15−xSix glassy ribbons with high Tx/Tm (> 0.70) and small ΔTm (ΔTm = Tm−Tx) promote the formation of high thermal stability of these alloys. The Si addition leads to an increase of Curie temperature TC of glassy ribbons from 181 K for x = 0 to 227 K for x = 7. The maximal magnetic entropy changes −ΔSM and RC values for magnetic field change of 50 kOe are about 4.70–5.20 J/kg K and 710–760 J/kg, respectively. The large RC values are due to the broad temperature range of the half maximum of ΔSM peak (∼ 200 K), which is caused by the change of the amorphous disorder structure. The moderate ΔSM and large RC values jointly make the Gd65Fe20Al15−xSix glassy ribbons promising candidates for magnetic refrigeration materials working at temperature range of 100–300 K.