Effect of Zn substitution on the one-dimensional metallic behavior of PrBa2Cu4O8

We have grown PrBa2(Cu1-xZnx)(4)O-8 single crystals with nominal compositions of x = 0, 0.05, 0.10, and 0.15, and measured the resistivity along a- and b-axis directions. For the Zn-free sample, the conduction along the b-axis direction was highly metallic, which persisted up to the x = 0.15 sample although the doping of Zn increased the resistivity. On the other hand, the a-axis resistivity of the Zn-frce crystal exhibited a peak around 130 K, which is attributable to a switching of the dominant conduction path from the Cu-O chain site at low temperature to the CuO2 plane at high temperature. With Zn doping, the peak moves to lower temperature and the resistivity extrapolated to T = 0 increases, indicating that Zn doping suppresses the coherent conduction across Cu-O chains. (C) 2001 Elsevier Science B.V. All rights reserved.