Influences of oxygen on the magnetocaloric properties of a Fe-based amorphous alloy

In this work, the Fe80P13C7 amorphous alloys containing a different amount of 53, 180, 241 and 270 at. ppm oxygen were synthesized and their magnetocaloric effect (MCE) was investigated. It was found that doping of oxygen can effectively regulate the Curie temperature (TC), magnetic entropy change (- ∆SM) and refrigerant capacity (RCFWHM) of alloys. Especially, with 241 ppm oxygen doping, the alloy showed TC of 597 K, - ∆SM of 2.47 J kg−1 k−1 and RCFWHM of 103.96 J kg−1 under 1.5 T, which were larger than that of most Fe-based amorphous alloys reported to date. The result from X-ray photoelectron spectroscopy confirmed that appropriate oxygen doping tends to translate interatomic bonds from p-d hybrid into Fe-Fe bonds, supporting the large TC and MCE. Our finding elucidates a new understanding of the role of oxygen in magnetic performance and may open up a new possible pathway for improving the MCE of Fe-based amorphous alloys.