Influence of Al substitution on the magnetocaloric and magnetoresistance effects of Ni46Co4Mn38Sb12-xAlx(0 ≤ x ≤ 2) alloys

Ni-Mn-Sb Heusler alloys exhibit a large magnetocaloric effect due to the magnetic structure coupling and are potential candidate for practical application. In this work, the effects of Al substitution for Sb on the magnetocaloric and magnetoresistance properties are investigated in Ni46Co4Mn38Sb12-xAlx(0 <= x <= 2) serial alloys. The results demonstrate that the critical temperature of martensitic transformation gradually increases with increasing Al concentration while the temperature interval between the beginning and ending of martensitic transition decreases till x = 0.5, then increases with further increasing of Al, resulting in the similar nonmonotonic behavior on both magnetic entropy and magnetoresistance for Ni46Co4Mn38Sb12-xAlx(0 <= x <= 2) series. Maximum value of 17.8 J/kg K and - 25.8% at 30 kOe is obtained respectively for magnetic entropy and magnetoresistance in Ni46Co4Mn38Sb12-xAl0.5, for the greatly narrowed temperature interval of phase transition after Al substitution