Preparation and Characterization of YBa2Cu3O2-δFilms Containing an Excess Amount of Cu by Chemical Vapor Deposition

YBa2Cu3O7-δfilms containing an excess amount of Cu were prepared on MgO(001) at 650-750°C by chemical vapor deposition using β-diketone metal chelates. In the films prepared at the low temperatures of 650°C and 700°C, the degree ofc-axis orientation was enhanced with increase of the Cu content from Y:Ba:Cu=1:2:3 to 1:2:4, and the films with Cu-rich content showed higherTcvalues than the films close to the stoichiometric composition. At the higher temperature of 750°C, a supplied excess of the Cu element affected the in-plane alignment of the grains and critical current density.