NON-FERMI-LIQUID BEHAVIOR AND SPIN FLUCTUATIONS IN DOPED UAL2

Using the canonical spin-fluctuation system UAl2 as a starting point, via negative chemical pressure (doping with Y) we have expanded d(U-U) in a system known to be near the Hill limit of f-electron localizatio n, and characterized the samples via resistivity, magnetic susceptibil ity, and specific-heat measurements. All system parameters, including magnetic susceptibility, specific heat gamma(=C/T lim(T-->0)), and spi n-fluctuation temperature, behave monotonically. For U1-xYxAl2, 0.30 l ess than or equal to x less than or equal to 0.70, spin-glass behavior is found with T-f similar or equal to 5.1+/-0.5 K. This spin-glass be havior weakens (T-f sinks, smaller magnetic signature, no specific-hea t anomaly) for x greater than or equal to 0.75 while, at the same time , the spin-fluctuation T(3)lnT term also gradually disappears from the specific heat. For x greater than or equal to 0.875, a non-Fermi-liqu id (nFl) lnT term is found in the low temperature C/T. This new, perha ps equilibrium, ground state persists upon further dilution of the U i ons with Y. Thus, we report on the evolution of nFl behavior in the ne ighborhood of a spin-glass ground state but, indeed, directly out of a yet weaker form of magnetism than heretofore reported, that of spin f luctuations.