Hall-Effect Studies of Bulk (R0.8Pr0.2)Ba2Cu3O7-y Systems (R = Yb, Er, Dy, Gd, Eu and Nd)

J. C. Chen；Yun-hui Xu；S. H. Cheng；L. C. Tung；M. K. Wu；Wei-Yan Guan

Chinese Journal of Physics

34卷2S期（1996 / 04 / 01）

243 - 251

英文

We report detailed studies of the normal state Hall-effect in bulk R0.8Pr0.2Ba2Cu3O7-y, samples (R = Yb, Er, Dy, Gd, Eu, and Nd). We find a linear temperature dependence of the Hall number nH above Tc. At a constant temperature nH is linearly dependent on ion-size of rare earth, viz. the larger R^3+ ionic radius, the lower nH. The cotangent of the Hall angle follows a universal T^2 dependence, i.e., cot өH = αT^2 + C. Both the slope α and the quantity C is insensitive to R ion and remains almost constant. On the basis of our data we proposed a Tc - nH diagram which manifests an ”underdoping””behavior of R0.8Pr0.2Ba2Cu3O7-y systems. We suggest that the strong hybridization between 4f-states of the Pr ion and the conduction band states in CuO2 planes, leading to the hole localization and the pair-breaking, are the mechanism for the suppression of superconductivity in R1-=PrxBa2Cu3O7-y systems.