Magnetocaloric Effect in Ni50Mn36Sb14–xZx (Z = Al, Ge; x = 0, 2) Heusler Alloys

Resumo

The temperature dependences of the electrical resistivity and magnetization of the Ni₅₀Mn₃₆Sb_14–xZ_x (Z = Al, Ge; x = 0; 2) alloys have been used to determine the characteristic phase transition temperatures. The isothermal entropy change ΔS was determined using Maxwell’s equation and the field dependences of magnetization. The partial substitution of Ge for Sb has been shown to result in a slight increase in ΔS and a shift in the ΔS maximum to the low-temperature range. The substitution of Al for Sb leads to a decrease in the effect and shift in the ΔS maximum to the high-temperature range. It has been found that the maximum magnetocaloric effect has been observed for the Ni₅₀Mn₃₆Sb₁₂Ge₂ composition and is equal to ΔS = 1.3 J/(kg K) in a field change of 10 kOe.