MAGNETIC-PROPERTIES OF INTERMETALLIC COMPOUNDS MN3PTCX (X=0-0.1)

Antiferromagnetic ordered alloy Mn3Pt with a Cu3Au-type structure has a triangular spin structure (D phase) below T(t) = 365 K and a colline ar one (F phase) between T(t) and the Neel temperature T(N)(F) = 475 K . The effect of carbon addition to Mn3Pt on magnetic properties is stu died for Mn3PtCx by measuring the magnetic susceptibility and pressure effect on the magnetic transition temperatures. The results show that (1) the lattice parameter expands with x, (2) both T(t) and T(N)(F) d ecrease with x. (3) T(t) decreases and T(N)(F) increases with pressure , (4) the F phase disappears at high pressures. The P-T magnetic phase diagrams are presented.