Magnetocaloric effect in Fe–Tm–B–Nb metallic glasses near room temperature

• (Fe0.76 − xTmxB0.24)96Nb4 amorphous alloys in bulk form were fabricated.
• The thermal stability, magnetic and magnetocaloric properties were investigated.
• Tm substitution enhances the GFA and tunes the TC to near room temperature.
• The Tm2Fe14B1 phase observed at higher Tm additions can influence the MCE.

Magnetic properties and magnetocaloric effect in (Fe0.76 − xTmxB0.24)96Nb4 (x = 0, 0.01, 0.05, 0.1, 0.17 and 0.18) metallic glasses have been studied. The appropriate substitution of Fe by Tm increases the glass-forming ability of the alloys and allows tuning the Curie temperature (TC) to near room temperature. A linear relationship between magnetic entropy change and saturation magnetization has been observed. The formation of minority nanocrystalline Tm2Fe14B1 phase has been observed at higher Tm additions, which could influence the magnetocaloric effect of the alloy. These Tm doped Fe-based alloys, with enhanced thermal stability, good magnetocaloric responses and tunable TC, are good candidates for near room-temperature magnetic refrigerants.