Large Magnetocaloric Effect and Magnetoresistance in Fe and Co Co‐Doped Ni‐Mn‐Al Heusler Alloys

The Ni40Co10−xFexMn33Al17 (x = 4, 6, 8) alloys are prepared by arc‐melting method. The crystallographic structure, magnetic and magnetoresistance properties are systematically studied. The large magnetic change is obtained across the martensitic transformation from the ferromagnetic austenite phase to weak‐magnetic martensite phase. With the increase in Fe/Co ratio, the martensite transformation temperature shifts to the lower temperature. The large values of magnetoresistance of 33.3, 25.7, and 13.1% are achieved at the field of 3 T for x = 4, x = 6, and x = 8 alloys around the martensitic transformation, respectively. These results indicate that Ni‐Fe‐Co‐Mn‐Al alloy provides the motive power for further research in practical applications.