The Structural, Magnetic, and Magnetocaloric Properties of Ni43Mn46-x Cu x In11 (x=0, 0.9, 1.3, and 2.3) Heusler Alloys

The effect of Cu alloying on the structural, magnetic, and magnetocaloric properties of the Mn-rich Ni43Mn46-x Cu (x) In-11 (x = 0, 0.9, 1.3 and 2.3) alloys was investigated with scanning electron microscopy, X-ray powder diffraction (XRD), and magnetization measurements. The substitution of Cu for Mn efficiently reduces the structural and magnetic transition temperatures of the Ni43Mn46In11 alloy. As a result, while the XRD pattern of the Ni43Mn46In11 alloy shows only tetragonal structure, the structures of Cu-doped alloys consist of both cubic and tetragonal phases at room temperature. The positive magnetic entropy changes (Delta S (M)) in the alloys were determined from the magnetic field-dependent magnetization measurements-M(H) using the Maxwell relation. Around the structural transition region, a maximum Delta S (M) was found 21.08 J kg(-1) K-1 for the Ni43Mn46-x Cu (x) In-11 (x = 2.3) alloy in a magnetic field change of 18 kOe.