Bulk properties of

Despite the recent report of zero thermal expansion in $\chem{YbGaGe}$, our extensive studies of the physical properties of pure $\chem{YbGaGe}$ failed to find anomalous behavior of the thermal expansion of both X-ray and dilatometry measurements. Instead, the temperature dependence of the lattice constants can be simply explained in terms of the Debye model with the cutoff frequency of 226$\un{K}$, which was estimated from heat capacity measurement. Additionally, susceptibility measurements have not revealed any sign of a change of the $\chem{Yb}$ valency from 2 to 700$\un{K}$, but magnetic correlations develop at low temperatures. Important findings of further interest are that $\chem{YbGaGe}$ has very strong low-lying optic phonons, 1.7 oscillator strength with an energy of 80$\un{K}$, and shows strong increase of Grüneisen parameter below 20$\un{K}$