Quantum critical behavior in an antiferromagnetic heavy-fermion Kondo lattice system (Ce_1-xLa_x)₂Ir₃Ge₅

The measurements on temperature dependences of magnetic susceptibility χ(T), specific heat C(T), and electrical resistivity ρ(T) were carried out for the antiferromagnetic (AFM) (Ce_1-xLa_x)₂Ir₃Ge₅ (0≤x≤0.66) system. It was found that the Neel temperature T_N decreases with increasing La content x, and reaches 0 K near a critical content x_cr=0.6. A new phase diagram was constructed based on these measurements. A non-Fermi liquid behavior in ρ(T) and a logT relationship in C(T) were found in the samples near x_cr, indicating them to be near an AFM quantum critical point (QCP) with strong spin fluctuation. Our finding indicates that (Ce_1-xLa_x)₂Ir₃Ge₅ may be a new platform to search for unconventional superconductivity.