Field ion microscopy for YBa2Cu3O7-x thin films

Thin high-temperature superconducting films were investigated for the first time by field-ion microscope (FIM). It was established in atomic scale, that ionic images of pure surface of thin films were identical to ionic images, earlier obtained from the pure surface of high-temperature superconducting ceramics and monocrystals. Analysis of real structure of crystal lattice of thin films in result of controlled removal of surface atoms by electric field enabled to visualize defects of structure with atomic resolution and establish, that for order degree in thin films was decreased, as compared to ceramics and monocrystals. Planar defect density was evaluated as 2x106cm-1 on the basis of data, obtained by FIM. Method for determination of c axis orientation in separate grains of polycrystalline thin film, using ionic micropictures of the surface was suggested. Method of producing emitter samples from YBa2Cu3O7-x thin films with 200-600A radius of peak curvature was described