Heavy-electron-like behavior in cubic PrCu(4)Au.

The magnetization M(H), magnetic susceptibility χ(T), electrical resistivity ρ(T) and specific heat C(T) properties of PrCu(4)Au have been investigated. A clear antiferromagnetic transition T(N) is observed at 2.5 K in C(T) and χ(T). The internal magnetic field at the Pr nucleus, H(HF), is obtained to be 195 T from the nuclear specific heat observed in C(T) below 0.7 K. The ground state of Pr 4f(2) in the cubic crystalline electric field is inferred to be a magnetic triplet Γ(5) from the magnitude of the magnetization at 2 K, which coincides with the value of the 4f(2) magnetic moments deduced from H(HF). The large value of the electronic specific heat coefficient, γ, remains at the zero-temperature limit even in external magnetic fields. On the other hand, the entropy up to T(N) is somewhat less than Rln3. These anomalous heavy-electron-like behaviors probably originate in the fact that both the magnetic moments and the quadrupole moments are involved in the ground state of Pr 4f(2).