Tunable Curie temperatures in Gd alloyed Fe–B–Cr magnetocaloric materials

The magnetocaloric effect of Fe80−xB12Cr8Gdx (x = 1, 2, 3, 5, 8, 10, 11) amorphous alloys was studied. Gd addition increases the thermal stability of the alloy and allows tuning the Curie temperature (TC). A linear relationship between the magnetic entropy change and the magnetic moment of the alloy was observed. The experimental values of magnetic field dependence of the magnetic entropy change were consistent with a phenomenological universal curve. The maximum magnetic entropy change, for x = 1, was ∼33% larger than Fe80B12Cr8, the refrigerant capacity (RC) is ∼29% larger than Gd5Si2Ge1.9Fe0.1 and within 10% of Fe82.5Zr7B4Co2.75Ni2.75Cu1 which is the best Fe-based amorphous MCM to date. The tunable TC can be used to increase RC and the temperature span of layered multi-composition magnetocaloric regenerators.

Research highlights▶ Magnetocaloric response of Fe80−xB12Cr8Gdx alloys was studied. ▶ Field dependence of magnetocaloric effect agrees with theoretical predictions. ▶ Refrigerant capacity was higher than Gd5Si2Ge1.9Fe0.1. ▶ Curie temperature could be tuned near room temperature. ▶ These alloys have potential as multilayered regenerators.