Preparation and characterization of Bi2Sr2CaCu2O8+δ thin films on MgO single crystal substrates by chemical solution deposition

Bi2Sr2CaCu2O8 thin films have been deposited on MgO single crystal substrates by spin-coating a solution based on 2-ethylhexanoate precursors. Pyrolysis takes place between 200 °C and 450 °C and is accompanied by the release of 2-ethylhexanoic acid, CO2 and H2O vapour. Highly c-axis oriented Bi2Sr2CaCu2O8 films were obtained after heat treatment at 840 °C in air. The highest Tc of 81 K was measured in a 10-layer film. Subsequent post-annealing in Ar and pure O2 did not improve the superconducting properties of the films and resulted in the appearance of Bi2CaCuO5 or Bi2(Sr, Ca)2CuO6 impurities.

► Bi2Sr2CaCu2O8 thin films were prepared on MgO substrates by solution deposition. ► X-ray pure, highly c-axis oriented films were obtained. ► A maximum Tc of 81 K was measured by AC-susceptibility. ► Annealing in O2 or Ar degrades the superconducting properties.