Nitrogen-Induced Change of Magnetic Properties in Antiperovskite-Type Carbide: Mn₃InC

The effects of N substitution on the magnetic properties of Mn₃InC_1-xN_x (0.0≤x≤0.7) are investigated systematically. Partial substitution of N for C leads to the monotonic reduction in both the Curie temperature T_C and saturated magnetization M_S. The final results obtained from thermo-magnetic curves demonstrate that Mn₃InC_1-xN_x samples show a magnetic phase transition from a paramagnetic (PM) state to a ferrimagnetic (FIM) state consisting of ferromagnetic (FM) and antiferromagnetic (AFM) components. In addition, there is a competition between the AFM component and the FM component in the FIM state with the change of the N-doped content. Magnetic measurements of Mn₃InC at 100 Oe and 5000 Oe indicate the metastability and the coexistence of different magnetic phases at lower temperature. The spans of FIM phase broaden gradually with further N doping. The mechanism for the induction of the complicated magnetic state is still in controversy. However, the results clearly show that the doping at the X site in antiperovskite Mn₃AX materials is as useful as that of the A and Mn sites.