Non-Fermi-liquid behavior in annealed UCu$_{4}$Pd

The effect of disorder in the polycrystalline UCu$_{4}$Pd system is addressed in an annealing study. Samples were annealed at 750$^{\circ}$C for 7, 14 and 56 days and compared to unannealed samples. X-ray diffraction data indicate that all samples are single phase UCu$_{4}$Pd. Magnetic susceptibility vs. temperature data and the Sommerfeld coefficient ($\gamma =C_{e}$/$T $where $C_{e}$ is the electronic specific heat) vs. temperature both show little variation with annealing and can be fit with either a logarithmic or weak power law function for 4.5K$\le T\le $50K and 0.6K$\le T\le $2K, respectively. In contrast, electrical resistivity vs. temperature data develop a Kondo-like minimum near 35K that strengthens with annealing. Additionally, at low temperatures (2K$\le T\le $10K), the resistivity is linearly proportional to temperature for all samples. These data indicate that the non-Fermi liquid behavior of UCu$_{4}$Pd is not suppressed by annealing and may resolve inconsistencies reported in previous studies. Data will be collected and presented for electrical resistivity at temperatures less than 2K. This work was supported by grants from the NSF and DOE.