High-Temperature Magnetocaloric Properties of Off-Stoichiometric Fe\(_{3}\)Al Alloys

In this study, we explored the structural, magnetic, and magnetocaloric properties of Fe \(_{3}\) $_3^{}$ Al off-stoichiometric samples prepared using the vacuum arc melting technique. X-ray diffraction studies confirmed the cubic \(D0_{3}\) $D{0}_3$ -type structure in these samples. M(H) curve revealed soft ferromagnetic behavior with low coercivity and good magnetic saturation. The magnetization vs temperature studies demonstrated a decrease in the Curie temperature from 906 to 620 K with an increase in Al composition. Notably, the Fe \(_{73}\) $_{73}^{}$ Al \(_{27}\) $_{27}^{}$ sample exhibited a substantial magnetic entropy change ( \(\varDelta \) $\Delta$ S \(_{M}\) $_M^{}$ = \(-\) $-$ 5.5 J kg \(^{-1}\) $_{}^{-1}$ K \(^{-1}\) $_{}^{-1}$ ) and a high relative cooling power (RCP = 307 J kg \(^{-1}\) $_{}^{-1}$ ) at 906 K. Further, the thermo-magnetic studies of these off-stoichiometric alloys have provided an insight into the Curie temperature dependency over the Al composition. The increase in the Al composition has shifted the Curie temperature towards the lower temperatures while changing the underlying crystallographic structure from B2 to \(D0_{3}\) $D{0}_3$ .