Quantum critical behavior in the heavy Fermion single crystal Ce(Ni _0.935Pd_0.065)₂Ge₂

We have performed magnetic susceptibility, specific heat, resistivity, and inelastic neutron scattering measurements on a single crystal of the heavy Fermion compound Ce(Ni_0.93BPd_0.06B)₂Ge ₂, which is believed to be close to a quantum critical point (QCP) at T = 0. At lowest temperature(1.8-3.5 K), the magnetic susceptibility behaves as _χ(T) - _χ(0) T^-1/6 with χ(0) = 0.032 × 10^-6 m³/mole (0.0025 emu/mole). For T < 1 K, the specific heat can be fit to the formula ΔC/T = γ₀ - T^1/2 with γ₀ of order 700 mJ/mole-K². The resistivity behaves as ρ = ρ₀ + AT^3/2 for temperatures below 2 K. This low temperature behavior for γ(T) and ρ(T) is in accord with the SCR theory of Moriya and Takimoto[1]. The inelastic neutron scattering spectra show a broad peak near 1.5 meV that appears to be independent of Q; we interpret this as Kondo scattering with T _K = 17 K. In addition, the scattering is enhanced near Q=(1/2, 1/2, 0) with maximum scattering at ΔE = 0.45 meV; we interpret this as scattering from antiferromagnetic fluctuations near the antiferromagnetic QCP.