Electrical resistivity of heavy-fermion system of cubic YbCu₅ under high pressures

Abstract Cubic YbCu₅ with an AuBe₅-type structure is one of the heaviest fermion systems in Yb- based compounds. In the Doniach diagram, its electronic state is in the vicinity of the quantum critical point. We examined the effects of pressure on the electrical resistivity p of cubic YbCu₅. It is found that there exists no evidence of magnetic ordering up to 2.9 GPa. The T² dependence of p at the lowest temperature, which corresponds to a Fermi liquid, is preserved up to 2.9 GPa. With increasing pressure, the T₂ coefficient A increases, while the Kondo temperature Tκ decreases; this suggests that the electronic state approaches the quantum critical point.