COEXISTENCE OF LOCALIZED AND (INDUCED) ITINERANT MAGNETISM AND HEAT-CAPACITY ANOMALIES IN GD1-XYXNI ALLOYS

The results of magnetization (M), electrical resistivity (rho), and he at-capacity (C) measurements for the alloys, Gd1-xYxNi, are reported. The x-ray-diffraction patterns indicate that there is a change in the crystal structure from CrB-type to FeB-type orthorhombic structure for increasing x near n=0.4. GdNi has been known to order ferromagnetical ly at 70 K and the observed x dependence of T-C and theta(p) proves th at the strength of Gd-Gd exchange interaction is enhanced by a factor of about 1.5 in the FeB structure. The M data suggest that there is an excess moment for the Gd-rich alloys. The observed magnetization beha vior is taken as an evidence to show that there is coexistence of loca lized magnetism (from Gd) and itinerant ferromagnetism of induced-type , presumably from Ni 3d band. There is an enhancement of C with decrea sing temperature above T-C over a wide temperature range presumably du e to short-range order effects in these alloys.