ANISOTROPIC RESISTIVITY IN THE MIXED STATE OF YBA2CU3O7-DELTA

Anisotropic YBCO film resistivity data of Iye et al. [Physica C 166 (1 990) 62] have been analyzed in terms of conventional flux-flow and pha se-slip resistivities. Iye et al. systematically varied the angle thet a of the magnetic field relative to the c-axis for a number of fields ranging from 0.3 to 5 T. It is shown that the data exhibit no evidence for conventional Bardeen-Stephen flux-flow; the data are interpreted using an expression for anisotropic phase-slip resistivity. The phenom enological expression for the resistivity given by Tinkham has been ex tended to include the dependence on the polar angle theta; the phase-s lip resistivity varies approximately as o(ps)(H,T,theta)=rho(n)/[I0(ga mma(H,T,theta)/2)]2. Although the mass anisotropy parameter GAMMA=5.3 (the ratio H(c2)(theta=pi/2)/(H(c2)(theta=0)), for low fields, the dat a for the ratio rho(H parallel-to c)/p(H perpendicular-to c) is as lar ge as 160 and the field and angular dependent resistivity does not sca le with H/H(c2)(theta); the variation is easily accommodated by the pr oposed model.