Growth of YBa2Cu3O7 Films with a Packet of Parallel Grain Boundaries Spaced by Nanometer Distances

Substrates with crystallographic orientation (100), consisting of (100)CeO–{(100)SrTiO3–(100)CeO2} × 4 epitaxial multilayer films oriented perpendicular to the surface, have been obtained by solid-phase bonding of Y-ZrO2 fianite crystals. The CeO2 and SrTiO3 layers were exposed on the film surface by their (100) planes and the (110) faces, respectively. All formed layers were 40 nm thick. Films of high-temperature superconductor (HTSC) YBa2Cu3O7 were epitaxially grows on the substrates; a packet of parallel grain boundaries, oriented perpendicular to the surface, was formed as a result of their inheritance from the {SrTiO3–CeO2} boundaries of the multilayer internal film. The YBa2Cu3O7 film is oriented by its (001) plane and (103) face above the CeO2 and SrTiO3 regions, respectively. Thus, a packet of eight parallel 45° grain boundaries, spaced by 40 nm, is formed in the YBa2Cu3O7 film. The current–voltage characteristic of a lithographic straight-line bridge in the HTSC film intersecting this packet contains eight steps, which correspond to eight bicrystal Josephson junctions, spaced by 40 nm and connected in series.