Study of Magnetostructural Phase transitions and Magnetocaloric Effects in Mn_65-xGa₁₇C_18+x (x = 0, 1, 3, 4)

A variety of magnetic materials show several properties, such as magnetic shape memory, large magnetoresistance, Hall Effect and magneto caloric effects. Several of these materials, also shows potential application in magnetic refrigeration technology. For example, the ternary alloy system Mn-Al-C (Al=Zn=Sn=In) exhibits face centered cubic ternary phase and has spontaneous magnetization. Recently it has been found that a similar magnetic ternary phase also occurs in the Mn-Ga-C system. Here we will present our results on structural, magnetic and magnetocaloric properties of Mn_65-xGa₁₇C_18+x (x =0,1,3,4) compounds. Detailed X-ray diffraction (XRD), and magnetization measurements will be shown. The occurrences of the structural transition, magnetic entropy change, magnetoresistance will be presented and discussed.