Effect of direct transport current and heat treatment on resistive properties of bismuth-based ceramic high-temperature superconducting oxides of various compositions

摘要

The effect of direct transport current (I) and heat treatment on resistive properties of bismuth-based ceramic high-temperature superconducting oxides of various compositions is studied by measuring the temperature dependent resistivity (r) at fixed points in the vicinity of liquid nitrogen temperature in the presence of Earth's uncompensated magnetic field. It is shown that the observed results are significantly dependent on the sample preparation and post-processing conditions as well as on the measurement temperature. The results obtained are interpreted within the framework of the theory of Josephson weak links modified under the impact of self magnetic field of the sample's transport current. An attempt is also done to find an analogy between the dependence of the characteristic parameters on the transport current in the case of heat treatment and on the dose when the samples are irradiated by various types of ionizing radiation.