Ca _3Pt ~(4+x)Ge _(13-y) and Yb _3Pt _4Ge _(13): New derivatives of the Pr _3Rh _4Sn _(13) structure type

摘要

The new phases Ca _3Pt _(4+x)Ge _(13-y) (x = 0.1; y = 0.4; space group I2 _13; a = 18.0578(1) ?; R _I = 0.063; R P = 0.083) and Yb _3Pt _4Ge _(13) (space group P4 _2cm; a = 12.7479(1) ?; c = 9.0009(1) ?; R _I = 0.061, R P = 0.117) are obtained by high-pressure, high-temperature synthesis and crystallize in new distortion variants of the Pr _3Rh _4Sn _(13) type. Yb _3Pt _4Ge _(13) features Yb in a temperature-independent non-magnetic 4f ~(14) (Yb ~(2+)) configuration validated by X-ray absorption spectra and resonant inelastic X-ray scattering data. Ca _3Pt _(4+x)Ge _(13-y) is diamagnetic (χ _0 = -5.05 × 10 ~(-6) emu mol ~(-1)). The Sommerfeld coefficient γ = 4.4 mJ mol -1 K -2 for Ca _3Pt _(4+x)Ge _(13-y), indicates metallic properties with a low density of states at the Fermi level in good agreement with electronic structure calculation (N(E _F) = 3.3 eV ~(-1)/f.u.)); the Debye temperature (D) is 398 K.