Effect of substitution of Ni by Cu on specific heat of CeNiSn

CeNiSn is an interesting heavy fermion compound, with its ground state bein g a Kondo insulator. The effect of the substitution of Ni by Cu on the spec ific heat of CeNi1-xCuxSn polycrystal samples is studied through the method of chemical element substitution. A series of samples (x = 0.0,0.02,0.06, 0.06) were prepared with an electric are furnace in the atmosphere of flowi ng high purity argon gas. X-ray powder diffraction analysis shows that all the final samples have single-phase structure,and that,with the increase of the substitution amount of Ni,the crystal parameters of the samples become larger. The specific heat measurements were performed with an adiabatic co lorimeter. The results indicate that the doping of Cu increases the specifi c heat at low temperature,and that the V-shape gap is gradually suppressed. The physical mechanism may be that the doping of copper brings about the K ondo lattice discorder and the increase in 3d electrons.