New Condo system of CeNiGa2 with strong orbital degeneracy

Thermoelectromotive force (α) and specific electric resistance (ρ) of CeNiGay (y=0.5, 2, 3) type compounds were investigated in order to study regularities of formation of state density fine structure close to the Fermi level (EF) in the systems with valent unstable (VU) rare earths. It is shown that for CeNiGa0.5 with the lowest Ga content ρ(T) curve is characterized by positive curvature with saturation at T>250 K; this is typical for systems with intermediate Ce valency. This is also supported by measurements of magnetic susceptibility. It is established that abnormally low energy of Ce 4f-level splitting by crystal field (Δ) at rather high Condo temperature (TK), TK≥Δ, is realized in CeNiGa2