  We report the crystal growth of a new compound, Yb3Os4Ge13, by using a
Bi-flux method. X-ray diffraction measurement shows that it crystallizes in the
quasi-skutterudite-type caged structure with a cubic space group of Pm-3n (No.
223). Magnetic measurements reveal almost fully localized Yb f-moments above
120 K. The resistivity exhibits a crossover from metallic to insulating
behavior with a logarithmic increase below ~ 40 K. The specific heat
coefficient shows a rapid upturn below ~5 K and exceeds 2 J mol-1 K-2 at 2 K.
Our experimental analysis and electronic band structure calculations
demonstrate that Yb3Os4Ge13 exhibits the Kondo effect due to strong
hybridization of the localized Yb f-moments with the p-electrons of the
surrounding Ge-cages.
