Quantum critical behavior in the heavy Fermion single crystal Ce(Ni${}_{0.935}$Pd${}_{0.065}$)${}_2$Ge${}_2$

Abstract

We have performed magnetic susceptibility, specific heat, resistivity, and inelastic neutron scattering measurements on a single crystal of the heavy Fermion compound Ce(Ni${}_{0.935}$Pd${}_{0.065}$)${}_2$Ge${}_2$, 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 $\chi (T)-\chi (0)$ $\propto$ $T^{-1/6}$ with $\chi (0)=0.032\times 10^{-6}$ m${}^3$/mole (0.0025 emu/mole). For $T<$ 1 K, the specific heat can be fit to the formula $\Delta C/T={\gamma }_0-T^{1/2}$ with ${\gamma }_0$ of order 700 mJ/mole-K${}^2$. The resistivity behaves as $\rho ={\rho }_0+A{T}^{3/2}$ for temperatures below 2 K. This low temperature behavior for $\gamma (T)$ and $\rho (T)$ is in accord with the SCR theory of Moriya and Takimoto\cite{Moriya}. 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 $\Delta E$ = 0.45 meV; we interpret this as scattering from antiferromagnetic fluctuations near the antiferromagnetic QCP.

to be published in J. Phys: Conference Series