重电子金属CeCu_(6-x)Ni_x低温电阻与比热的研究

Investigation of the low-temperature resistance and specific heat of heavy fermion compounds CeCu_(6-x)Ni_x

测量了重电子金属CeCu6 -xNix(x =0 ,0 0 5 ,0 1,0 15 ,0 2 ) 0 1K— 2 5 0K的低温电阻和 5K— 70K低温比热 ,发现样品电阻的极大值温度随着掺Ni含量的增大而急剧下降 ,这一现象反映少数与Ni邻近的Ce离子在极低温下磁矩的加强和整个Ce离子点阵对导电电子相干散射的减弱 .与此相反 ,低温电子比热系数γ在较低温度下近于常数 ,而在 8K附近因有效质量变大而明显上升 ,但γ明显上升的温度 ,对Ni的含量却不敏感 。

In this paper, the experimental results of the low temperature resistance between 0\^1K to 250K and specific heat between 5K to 70K of heavy fermion compounds CeCu 6 x Ni x ( x =0 0,0 05,0 1,0 15,0 2) are reported. The doping effect of the Ni content on the low temperature properties of CeCu 6 is studied. The temperatures of resistance maximuas of the samples reduce dramatically with the increase of the doping content x . This indicates the enhancement of magnetic moment of minor Ce ions that are neighboring Ni atom and the decrease of the coherent scattering between the whole Ce ion lattice and the conduction electrons. The low temperature electronic specific heat coefficient γ ( C E/ T , where C E is the electronic specific heat) is nearly a constant at low temperatures, but it apparently increases below 8K due to the increase of its effective mass. However, the temperature at which γ begins to increase is not sensitive to the content of Ni, indicating that the status of most cerium ions are not affected.