Cu掺杂对Kondo绝缘体CeNiSn低温比热的影响

CeNiSn是一种很有趣的重费米子化合物，其基态为Kondo绝缘体.采用化学元素替代的方法研 究Cu掺杂对CeNiSn多晶样品低温比热的影响.在流动高纯氩气的保护下，用电弧炉制备了一 系列的多晶样品CeNi_1-xCu_xSn(x＝0，002，006，008).X射 线粉末衍射分析表明，制备出来的样品均为单相多晶.随着Cu掺杂量的增加，样品的晶格参 数增大.采用绝热热脉冲法测量样品的比热，结果表明随着Cu掺入量的增加，相应样品的低温比热也随之增大，能隙逐渐减小 关键词： 重费米子 Kondo绝缘体 CeNiSn 比热 反铁磁有序

EFFECT OF SUBSTITUTION OF Ni BY Cu ON SPECIFIC HEAT OF CeNiSn

CeNiSn is an interesting heavy fermion compound,with its ground state being a Kondo insulator.The effect of the substitution of Ni by Cu on the specific heat of CeNi 1-x Cu\- x Sn 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 arc furnace in the atmosphere of flowing 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 colorimeter.The results indicate that the doping of Cu increases the specific 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 Kondo lattice discorder and the increase in 3d electrons.