Phase 2234 in Pb- and Sb-doped Bi-Sr-Ca-Cu-O films

The phase 2234 with four layers of Cu-O is synthesized in Bi-Sr-Ca-Cu thin films deposited in vacuum onto MgO single crystal substrates by thermal evaporation of components from one or several source. The phase 2234 is formed in Sb- and Pb-doped films during high-temperature annealing at 840-850 deg C in the oxygen-rich atmosphere. The formation of the phase causes changes in the electric properties of the doped samples. In the films containing the phase 2234 the critical temperature of the superconducting transition onset was observed to rise to 120 K