Magneto-transport study of a Bi2223 superconductor produced by a high-pressure method

Abstract

Various physical properties of a high-pressure made ceramic have been studied in the normal state and mixed state region, mainly from the point of view of transport properties. The electrical resistivity, the thermoelectric power and the Nernst effect are reported for a broad temperature range and for fields between 0 and 4 T. Derived physical parameters like the excess (integrated) properties, the behaviour of the percolation line(s) as a function of temperature and field, the so-called transport energy, and the so-called activation energies, the Ginzburg - Landau parameter and the thermal Hall angle field and temperature dependence are given and briefly compared with previous reports. We point out that in the region examined, the so-called percolation lines differ whether the transport coefficient is purely electrical or is electrothermal in nature. We point out that the thermal Hall angle temperature is the same as the thermoelectric percolation temperature. Finally we examine for the first time in such systems the behaviour of the so-called `electrothermal conductivity'. Through a kinetic formalism using either an s-wave or a d-wave-like order parameter, we point out that the field dependence is quite different in the mixed state near the critical temperature. This allowed us to decide that the signature for a d-wave nature of the gap parameter exists for such transport properties near the critical temperature. .