Growth behaviour and superconductivity of BiSrCaCuO films on MgO(100) substrates

• Published in: Thin solid films 1990-02, Vol.185 (1), p.159-167
• Main Authors: Lin, W.T., Chu, H.C., Chu, Y.L., Lin, H.S., Fang, Y.K., Chang, C.Y., Wu, P.T., Kung, J.H.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Superconductivity
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/0040-6090(90)90015-6

The formation temperatures of Bi 2 Sr 2 CuO x (2201) and Bi 2 Sr 2 CaCu 2 O x (2212) phases are about 550°C and 775°C respectively for sputtered films on MgO(100) substrates. A preferred grain growth appeared at 820°C. A reversible transformation between the 2201 and 2212 phases was observed in the temperature range 780–870°C. Two-step annealing enabled the zero-resistance temperature T 0 of films with non-stoichiometric composition to be higher than 78K. The syntactic growth of the 2201 and 2212 phases, and the twin and the low angle grain boundary of the 2212 phase were also present. Two modes of localized epitaxial growth of 2212 grains on MgO(100) substrates were observed. The orientation relationships between the 2212 overlayer and the MgO substrate are (001) 2212(100) MgO and [100] 2212[011] MgO, and (001) 2212(100) MgO and [100] 2212[010] MgO. No interfacial reaction between the BiSrCaCuO film and the MgO substrate during heat treatment was observed.