Abstract:
Effect of carbon content on magnetostructural transformation in antiperovskites of the type Mn(3)GaC(x) (x=0.8, 1.0 and 1.05) has been investigated. It is found that increase in carbon content changes the ground state from ferromagnetic metallic (x=0.8) to antiferromagnetic semiconducting (x=1.05) type. This has been attributed to localization of itinerant Mn 3d electrons due to increased Mn3d - C2p hybridization. Such a hybridization strengthens Mn-C-Mn antiferromagnetic interactions over Mn-Mn ferromagnetic interactions. Further, magnetic field can be used as a tool to modulate the relative strengths of these ferromagnetic and antiferromagnetic interactions thereby affecting the nature and strength of magnetocaloric properties.
