Influence of Bi doping on the in situ growth of TlBa sub(2)Ca sub(2)Cu sub(3)O sub(9) high-T sub(c) films

• Published in: Journal of superconductivity 1998-10, Vol.11 (5), p.603-607
• Main Authors: Reschauer, N, Wagner, H H, Brozio, W, Spreitzer, U, Schauer, T, Renk, K F, O'Connor, J D, Dew-Hughes, D, Goringe, M J, Grovenor, C R M, Kaiser, T, Piel, H
• Format: Article
• Language: English
• ISSN: 0896-1107

The in situ process - laser ablation in combination with thermal evaporation of Tl sub(2)O - has turned out to be a preparation method for single-phase and epitaxial TlBa sub(2)Ca sub(2)Cu sub(3)O sub(9) (1223) thin films with T sub(c) values up to 109 K. It was found by several groups that a partial substitution of Tl by Bi simplifies the phase development of the 1223 compound in the usual two-step process. We have investigated the influence of the Bi doping on the in situ growth. X-ray measurements show that the films consisted mainly of the 1223 compound. In 300-nm thin films there was no evidence of a Bi amount in the crystal structure, but thinner films (80 nm) show a small amount of Bi. We concluded that Bi doping supports the phase development of the 1223 compound only in an early stage of the film growth. The Bi-doped films have higher T sub(c) values up to 114 K, higher j sub(c) values up to 6 x 10 super(5) A/cm super(2) (77 K, 0 T), and lower surface resistances of 56 m Omega (77 K, 87 GHz) than the undoped films.