Pinning effect of misfit dislocations in YBa_2Cu_3O_(7-y) superconducting film by liquid phase epitaxy

摘要

YBa_2Cu_3-O_(7-y) (YBCO) thick films were prepared by liquid phase epitaxy on the single crystalline substrates. The microstructure of the YBCO was investigated by high resolution transmission electron microscopy. Microstructure of the films is dominated by the misfit of the lattice constant between the YBCO and the substrate. Misfit dislocations are introduced to relax the stress due to lattice misfit between the YBCO layer and the substrate. The residual stress caused other kinds of defects in the YBCO films. The defects introduce to the YBCO films behave as the effective prinning centers to enhance the pinning force in the magnetic field.