MAGNETIC-BEHAVIOR OF MN3GA1-XALXC UNDER HIGH MAGNETIC-FIELD AND HIGH-PRESSURE

Mn3GaC is antiferromagnetic (AF) below T-t similar to 160 K and ferrom agnetic (F) above T-t. The application of pressure enhances the Mn mom ent in the F state and produces an intermediate state between the AF a nd F states. Mn3GaC shows a metamagnetic transition to the F state bel ow T-t. From the transition fields, the electronic specific heat coeff icient in the F state is estimated to be gamma = 43 mJ/K-2 mol, which is extremely large. The substitution of Al for Ga in Mn3GaC produces t he same effect as the application of high pressure.