Anisotropy of the resistivity in the a-b plane of a superconducting YBa2Cu3O7-δ single crystal

Abstract

We have measured the in-plane longitudinal resistivities pa and pb as functions of temperature and magnetic field. The measurements were all made on the same detwinned single crystal of YBa2Cu3O7-δ (YBCO). Defining Tc to be at the onset of resistance, it is the same for pa and Pb, in a magnetic field ranging from 0 to 3.5 T. In zero field, Tc = 93.4 K, so the oxygen doping of the crystal was approximately optimal. In the mixed state, the anisotropy ratio of the resistivities (pa/pb) decreases with decreasing T or H, and the chain conductivity (σb σa) is smaller than the plane conductivity (σa). Both σa and σb increase with decreasing temperature, and so does (σb-σa). © 1996 Plenum Publishing Corporation.