Growth and characterisation of Bi-2212 crystals and improvement of Bi-2212/Ag superconducting tapes

The aim of this study was to identify and explore possible ways to improve the critical current density of Bi-2212/Ag tapes. The work was divided into two parts: growth and characterisation of Bi-2212 crystals; and improvement of Bi-2212/Ag superconducting tapes. In the first part, the focus was on growing high quality Bi-2212 single crystals in order to gain knowledge in relation to the formation of Bi-2212 phase, the uptake and release of structural oxygen from B-2212 crystal structure, the relation between critical transition temperature and cation stoichiometry. Also, due to some uncertainty regarding the fundamental parameters of the Bi-2212 phase such as the higher critical field (Hcz), penetration depth (k) and coherence length (Q, good quality Bi-2212 single crystals were used for measurements of these parameters. The knowledge gained in the first part of this study was used in the second part as a basis for the design of new procedures to increase the critical current density of Bi- 2212/Ag tapes.