Magnetic Susceptibility, Electrical Resistivity, and Specific Heat Measurements of the filled Skutterudite PrOs$_4$As$_{12}$

Single crystals of PrOs$_{4}$As$_{12}$ were grown by a flux method. Measurements on single crystals of PrOs$_{4}$As$_{12}$ reveal antiferromagnetic ordering at a N\'{e}el temperature near 2.2 K. Low-temperature electrical resistivity, $\rho $(T), measurements indicate that T$_{N}$ is completely suppressed by fields of 1.5 T, while ac magnetic susceptibility and magnetization measurements reveal a metamagnetic transition at temperatures near the N\'{e}el temperature for low fields. High temperature Curie-Weiss fits yield an effective moment, $\mu _{eff}$ = 3.8 $\mu _{B}$, higher than the Pr$^{3+}$ free ion value $\mu $ = 3.58 $\mu _{B}$ derived from by Hund's rules. Fits to specific heat data above T$_{N}$ reveal a moderately enhanced electronic specific heat coefficient, $\gamma \quad \sim $ 100 mJ/mol K$^{2}$. The temperature dependence of $\rho $ and the negative magnetoresistance are indicative of Kondo lattice behavior. Research at UCSD supported by the U.S. DOE and NSF.