c-axis magnetotransport in CeCoIn5 -: art. no. 184506
c-axis magnetotransport in CeCoIn5 -: art. no. 184506
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DOI：
10.1103/physrevb.72.184506
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发表时间：
2005-11-01
影响因子：
3.7
通讯作者：
Thompson, JD
中科院分区：
文献类型：
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作者：
Malinowski, A;Hundley, MF;Thompson, JD
我们给出了重费米子超导体CeCoIn 5在40 mK至400 K温度和高达9 T磁场下的面外电输运测量结果。对于T < 10 K的输运测量表明，零场电阻率rho（c）随温度线性变化，并在0 K时外推至接近零，表明与量子临界点（QCP）相关的非费米液体（NFL）行为。CeCoIn 5的纵向磁阻（LMR）对于平行于c轴施加的场是负的，并且在50和100 K之间按B/（T+T-*）缩放，揭示了类似于2 K的单杂质Kondo能量标度T-* 的存在。从16 K开始，一个小的正LMR功能是明显的字段小于3 T的增长幅度随温度降低。对于更高的领域，LMR是负的，并随着温度的降低而增加。这种相当大的负磁阻从2.6 K到大约8 K按B-2/T缩放，并且它由外推的剩余电阻率引起，该剩余电阻率在NFL温度状态下变为负值并且随场二次增长。沿c轴沿着施加磁场，其中B > B-c2，在T小于130 mK时恢复了ρ（c）（T）中的费米液体行为。T-2电阻率系数的场依赖性的分析表明，QCP在CeCoIn 5位于低于上临界场，超导相内。这些数据表明，虽然高T的C轴运输CeCoIn 5表现出典型的重费米子系统的功能，低T运输是由自旋波动与QCP和近藤相互作用的影响，由底层复杂的电子结构固有的各向异性CeCoIn 5晶体结构。
We present the results of out-of-plane electrical transport measurements on the heavy fermion superconductor CeCoIn5 at temperatures from 40 mK to 400 K and in magnetic field up to 9 T. For T < 10 K transport measurements show that the zero-field resistivity rho(c) changes linearly with temperature and extrapolates nearly to zero at 0 K, indicative of non-Fermi-liquid (NFL) behavior associated with a quantum critical point (QCP). The longitudinal magnetoresistance (LMR) of CeCoIn5 for fields applied parallel to the c axis is negative and scales as B/(T+T-*) between 50 and 100 K, revealing the presence of a single-impurity Kondo energy scale T-*similar to 2 K. Beginning at 16 K a small positive LMR feature is evident for fields less than 3 T that grows in magnitude with decreasing temperature. For higher fields the LMR is negative and increases in magnitude with decreasing temperature. This sizable negative magnetoresistance scales as B-2/T from 2.6 K to roughly 8 K, and it arises from an extrapolated residual resistivity that becomes negative and grows quadratically with field in the NFL temperature regime. Applying a magnetic field along the c axis with B > B-c2 restores Fermi-liquid behavior in rho(c)(T) at T less than 130 mK. Analysis of the T-2 resistivity coefficient's field dependence suggests that the QCP in CeCoIn5 is located below the upper critical field, inside the superconducting phase. These data indicate that while high-T c-axis transport of CeCoIn5 exhibits features typical for a heavy-fermion system, low-T transport is governed both by spin fluctuations associated with the QCP and Kondo interactions that are influenced by the underlying complex electronic structure intrinsic to the anisotropic CeCoIn5 crystal structure.