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Quantum Critical Fluctuations in the Heavy Fermion compound Ce(Ni0.935Pd0.065)2Ge2

Cuihan Wang (University of Calidornia-Irvine)

We performed inelastic neutron scattering experiments together with magnetic susceptibility and specific heat measurements on a single crystal of the heavy Fermion compound Ce(Ni0.935Pd0.065)2Ge2 , which is believed to exhibit a quantum critical point (QCP) at T = 0. The magnetic susceptibility shows enhancement from Curie-Weiss behavior but no long range order is observed. The specific heat follows non-Fermi-liquid behavior of the form C/T~ln(T0/T), but it can also be fit to the formula C/T = .0 - dT1/2 with .0 of order 600 mJ/mole-K2. Inelastic neutron scattering spectra show an antiferromagnetic fluctuation peaked at QN =(1/2 1/2 0) in the Brillouin zone. The temperature dependence of the energy scans at QN show that both the inverse correlation lifetime . and the inverse staggered susceptibility .(QN) follow a + bT3/2 behavior. This behavior, together with the T1/2 behavior of the specific heat, follows the SCR theory of Moriya and Takimoto,, with the important caveat that a . 0 means that the correlation time does not diverge at the QCP.

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