Physica C: Superconductivity 399, 22 (2003)

F. Mrowka, S. Manzoor, P. Pongpiyapaiboon, I. L. Maksimov, P. Esquinazi, K. Zimmer and M. Lorenz

Abstract

With a multiterminal technique we have studied the behavior of the in-plane voltage in high-T_c superconducting YBa₂Cu₃O₇ films as a function of temperature T, magnetic field B and distance from the input current electrodes. Regions with different superconducting transition temperatures were obtained by selective sputtering between gold electrodes. The non-local voltages, measured outside of the direct current path, show an excess signal near the critical temperature T_c(B) which resembles that measured in different superconductors and attributed partially to charge imbalance effects, the presence of phase-slip centers and vortex–antivortex-interactions. We have determined the decay length of the non-local voltages as a function of field and temperature. We compared and analyzed the excess voltage and decay length with a current distribution model and an equivalent circuit of resistances. This model accounts for all the measured behavior of the non-local voltages and of the decay length. We discuss also estimates of the decay length based on charge imbalance and vortex correlations models.