Transmission electron microscopy study of rf-sputtered (Bi, Pb)_2Sr_2Ca_2Cu_3O_6 thin films on MgO substrates

摘要

The interface of epitaxial c -axis-oriented (Bi, Pb)2 Sr2 Ca- Cu O thin films grown by rf sputtering on MgO substrates has been investigated by highresolution transmission electron microscopy. It was found that, in spite of the roughness of the substrate surface, the lattice of the film oriented so that its (002) planes are parallel to the interface. No impurity phase was detected at the interface. Near the substrate the presence of the 2201 phase was observed, with some 2212 phase farther from the substrate, whilst the bulk of the film is 2223 phase with some intergrowth of 2212 phase. From selected-area electron diffraction patterns taken at the interface, it was observed that the large lattice mismatch between the film and MgO substrate did not prevent excellent alignment.