The role of boron on the magneto-caloric effect of FeZrB metallic glasses

Fe-rich FeZrB metallic glasses exhibit magneto-caloric effect (MCE) around room temperature. Amorphous ribbons of two different compositions, Fe 91Zr 7B 2 and Fe 88Zr 8B 4, with respective Curie temperature values of 230 and 285 K have been studied. Although the maximum magnetic entropy change is relatively moderate ( | Δ S M | max ∼ 3 J K −1 kg −1 under an applied magnetic field change from 0 to 50 kOe), the MCE spreads over a broad temperature interval ( ∆T ∼ 200 K), giving rise to a large refrigerant capacity loss (RC ∼ 435 J kg −1) without any hysteresis. The Curie temperature can be easily tuned between 200 and 350 K by changing the boron content. Therefore, the MCE can be controlled over a wide temperature interval, thus making these amorphous alloys promising candidates for magnetic refrigeration near room temperature.