Structural And Physical Properties Of The Quasiskutteruditesr R₃Os₄Ge₁₃（R=Yb,Y）

The research about the quasiskutterudites R3T4X13 has attracted much interest in the past decades. Efforts in recent years have witnessed a continuous expansion of the R3T4X13 family, leading to the discovery of many exotic properties. R can be a rare-earth or an earth alkaline element, T can be a transition metal from 3d to 5d, and X can be either a group-III or a group-IV element. These compounds typically crystalize into the same primitive cubic crystal structure with a space group Pm-3n, but show remarkably different properties depending on the choice of the three elements.The work of this paper includes two aspects: Kondo effect in the quasiskutterudite Yb3Os4Ge13, the superconductivity of low carrier density in Y3Os4Ge13 polycrystal.Yb3Os4Ge13 single crystals were first grown by Bi flux method. X-ray diffraction measurement revealed that it crystallizes in the quasiskutterudite-type caged structure with a cubic space group of Pm-3n(No.223). Magnetic measurements revealed almost fully localized Yb 4f-moments above 120 K. The resistivity exhibited a logarithmic increase below ~ 40 K. The specific heat coefficient g showed a rapid upturn below ~5 K and exceeds 2 J/ mol×K2 at 2 K. Our experimental analysis and electronic band structure calculations demonstrated that Yb3Os4Ge13 exhibits the Kondo effect due to strong hybridization of the localized Yb f-moments with the p-electrons of the surrounding Ge. Yb3Os4Ge13 polycrystal was synthesized by an arc melting method. Similar Kondo effect was confirmed through the same measurement and analysis. Our research well achieve a comprehensive understanding on the role of the T site element from 3d to 5d in R3T4X13 families.Y3Os4Ge13 polycrystal was first synthesized by an arc melting method. A superconducting transition was confirmed and characterized through the measurements and analysis of magnetism, resistivity and heat capacity, Tc~3.3 K. Resistivity measurement showed that it is a typical semi-metallic compound. The analysis of magnetism data suggested that it is a type-II superconductor.