A modified vortex glass correlation length is introduced to give a consistent description of the field and temperature dependence of the resistivity in the vortex liquid regime of high- $T_c$ superconductors. The proposed model explicitly takes into account both thermal energy and a characteristic mean pinning energy, $U_0(B,T)$. We find good agreement between the model and our measurements on twinned single crystals of ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ and thin film ${\mathrm{Tl}}_2{\mathrm{Ba}}_2{\mathrm{CaCu}}_2{\mathrm{O}}_{8+\delta }$.

• Received 16 December 1998

DOI:https://doi.org/10.1103/PhysRevLett.83.1850