THERMODYNAMIC AND MAGNETIC-PROPERTIES OF (NI1-XMX)3AL WITH M = CU ANDPD AND NI3(AL1-XSIX)

The ferromagnetic transition temperature T(c) of Ni3Al is found to be about 60 K for a polycrystalline sample with 76 at. % Ni content and 8 1 K for a single crystal with 76.6 at. % Ni. Our magnetization measure ments show that when Cu or Pd is substituted for Ni in Ni3Al, T(c) dec reases with increasing Cu or Pd concentration and goes to zero in the vicinity of the critical concentrations of 2% Cu or 10% Pd. When Si is substituted for Al, T(c) also decreases and goes to zero at a critica l concentration of about 10% Si. Specific heat studies indicate that t he electronic specific heat coefficient gamma is slightly enhanced whe n these systems approach their critical concentrations. This behavior is discussed in terms of the self-consistent renormalization theory fo r nearly and weakly itinerant magnets.