Effect of transport current on the Bi-containing sample electric and magnetic properties

The paper deals with the effect of transport current on the behaviour of dynamic magnetic susceptibility of ceramic high-temperature superconductors. It is shown that temperatures of superconducting transitions of intergranular space and ensemble of granules at low values of transport current depend nonlinearly on transport current. This behaviour is explained qualitatively. Scaling nature of temperature dependence of the real part of susceptibility on temperature in the vicinity of Tc is confermed; this fact points to the percolation nature of bismuth system conditivity. It is shown that energy gap value near sample surface significantly differe from that of bulk value. The effect of transport current on the ratio between energy gap near the surface and that in the bulk is studied