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用气相输运法制备了准一维结构的NbSe_3单晶,并研究了其剩余电阻率与杂质的关系。在电子扫描电镜(SEM)下观测了NbSe_3单晶的表面形貌,未见亚微米尺寸的缺陷。NbSe_3单晶的电阻温度与温度的关系(ρ-T)曲线表明,NbSe_3样品分别在T_(ρ1)=145 K和T_(ρ2)=57 K 经历两次 Peierls相变、剩余电阻比 RRR高于 200。根据对不同样品的ρ-T曲线的研究指出,以前的文献用剩余电阻比估计杂质浓度n_i的方法是一个错误,并提出了改进措施。
The quasi one-dimensional structure of NbSe_3 single crystal was prepared by vapor transport method and the relationship between the residual resistivity and impurities was studied. The surface morphology of NbSe_3 single crystal was observed under scanning electron microscope (SEM), and no submicron size defects were observed. (Ρ-T) curves of NbSe_3 single crystal show that the samples of NbSe_3 undergo two Peierls transformations at T ρ1 = 145 K and T ρ2 = 57 K respectively, and the residual resistance ratio is higher than RRR 200. According to the study of ρ-T curves of different samples, it is pointed out that the former method of estimating the impurity concentration n_i by the ratio of residual resistance is a mistake and some improvement measures are proposed.