Influence of non-magnetic Cu on structural, magnetic and magnetocaloric properties on NiMnIn bulk Heusler alloys

The structural, magnetic, and magnetocaloric characteristics of bulk Cu-doped Ni47Mn40-sCusIn13 Heusler alloys (s = 0 and 1) were investigated. Temperature-dependent magnetizations for Ni47Mn40-sCusIn13 (s = 0 and 1) were performed under a magnetic field (H) 0.05 T. The substitution of Copper (Cu) for Manganese (Mn) reduces the structural as well as magnetic phase transition temperatures. At room temperature (RT), PXRD pattern of Ni47Mn40-sCusIn13 (s = 0 and 1) bulk Heusler alloys shows that both samples have a cubic structure. The copper substitution in the Mn-site shifts the martensitic transformation temperature to the low temperature side as valence electron concentrations (e/a) decrease [MS = 288 K for s = 0 and MS = 251 K for s = 1]. The isothermal magnetization [M(H)] curve in the vicinity of the martensitic transition for s = 1 alloy exhibits the typical metamagnetic behavior that is not present for s = 0 Heusler alloys. The alloys reveal positive magnetic entropy changes (& UDelta;SM) for s = 0 and 1 respectively. A maximal & UDelta;SM of 10 J.kg-1K- 1 at a temperature of 248 K has been obtained in the s = 1 compare than & UDelta;SM of 1.27 J.kg-1K- 1 (s = 0) alloys for a field change of 0-5 T.

Automated summary

The structural, magnetic, and magnetocaloric characteristics of bulk Cu-doped Ni47Mn40-sCusIn13 Heusler alloys were studied. Copper substitution in the Mn-site reduces the structural and magnetic phase transition temperatures. The alloys exhibit metamagnetic behavior and positive magnetic entropy changes, with the s = 1 alloy showing a higher maximal magnetic entropy change compared to the s = 0 alloy.