Behaviour of the superconductivity characteristics of the Bi system during water soaking

Abstract

Samples of a bulk Bi-Pb-Sr-Ca-Cu-O system and a thick film of the Bi-Sr-Ca-Cu-O system are soaked in distilled water and the change in the superconductivity characteristics is measured. For the bulk samples, the maximum magnetization in the magnetization curve and the critical current density increase for the first 18 hours of soaking and then decrease during the subsequent soaking time. The critical temperature shows monotonic decrease throughout the soaking. A thick-film sample is almost the same as a bulk sample, i.e. the critical current density of the thick film first tends to increase for a short time due to its greater surface area then tends to decrease during the subsequent soaking. The critical temperature of the film sample also shows a slight deterioration as a result of the water soaking.