重费密子系统CeCu6-xNix的极低温电阻研究

CeCu₆是一种重费密子系统,采用Ni替代Cu研究磁性原子掺杂的多晶样品CeCu_6-xNi_x(x=0.00,0.05,0.10,0.15,0.20)在极低温下的电阻随温度的变化规律.实验结果表明,随着Ni原子掺杂量的增加,电阻的规律发生变化.在500mK以下,x≈0.1的样品电阻与温度呈线性关系,表现出非费密液体行为,而其他样品皆为典型的费密液体,x≈0.1是其临界掺杂成分.对比用Au替代的情况,临界掺杂成分也是0.1,但Au掺杂是靠体积膨胀来改变合金的基态性质,而Ni掺杂则是因其磁性造成对合金基态性质的影响 关键词： 重费密子 临界掺杂 非费密液体

STUDY OF THE ULTRA-LOW TEMPERATURE RESISTANCES OF HEAVY FERMION SYSTEM CeCu6-xNix

CeCu₆ is one of heavy fermion materials. The effect of the partly substitution of Cu by Au, Ag, Pd and Pt on the low temperature properties has been intensively studied. In this paper, we study the temperature dependence of resistance of CeCu_6-xNi_x(x=0.00, 0.05, 0.10, 0.15, 0.20) at temperatures below 1K. Experimental result shows that the temperature dependence of resistance changes with increase of doping content x. Below 500mK, the resistance of sample with x≈0.1 has a linear temperature dependence, showing a typical non-Fermi liquid behavior, while other samples behave as Fermi liquid. This means x≈0.1 is the critical doping for this system. In the case of Au substitution of Cu, the critical doping of which is also x=0.1, the ground state of the system is changed from Fermi-liquid to non-fermi liquid and antiferromagnetic ordering by volume expansion. But in the present case, the ground state of Ni doping systems changes from FL to NFL due to the magnetism of Ni.