Wang C H, Poudel L, Taylor A E, Lawrence J M, Christianson A D, Chang S, Rodriguez-Rivera J A, Lynn J W, Podlesnyak A A, Ehlers G, Baumbach R E, Bauer E D, Gofryk K, Ronning F, McClellan K J, Thompson J D
Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. University of California, Irvine, CA 92697, USA.
J Phys Condens Matter. 2015 Jan 14;27(1):015602. doi: 10.1088/0953-8984/27/1/015602. Epub 2014 Dec 3.
Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experiments were performed on a single crystal of the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T ⩽ 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP (ρ(T) ∼ T(3/2) and γ(T) ∼ γ0 - bT(1/2)). However, for 2 ⩽ T ⩽ 10 K, the susceptibility and specific heat vary as log T and the resistivity varies linearly with temperature. Furthermore, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. We suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.
为了研究反铁磁（AF）量子临界点（QCP）附近的自旋涨落，我们对重费米子化合物Ce(Ni0.935Pd0.065)2Ge2的单晶进行了电阻率、比热、磁化率和非弹性中子散射实验。对于T⩽1 K，电阻率和比热系数呈现出三维巡游AF QCP预期的幂律行为（ρ(T) ∼ T(3/2) 且γ(T) ∼ γ0 - bT(1/2)）。然而，对于2⩽T⩽10 K，磁化率和比热随log T变化，电阻率随温度线性变化。此外，尽管电阻率和比热呈现出QCP预期的非费米液体行为，但自旋涨落的关联长度、关联时间和交错磁化率在低温下仍保持有限。我们认为，这些与QCP预期的发散行为偏差可能源于合金无序。
