Artificial grain-boundary Josephson junctions were fabricated by using a new bi-epitaxial technique. The boundaries could be obtained by controlling the orientation of a MgO seed layer, and were characterized by a misalignment of the c-axes (45º c-axis tilt or 45º c-axis twist). A detailed characterization of the Josephson properties revealed marked differences in the transport parameters of tilt and twist junctions. High-resolution electron microscopy revealed the presence of perfect basal plane faced boundaries in the cross-sections of tilt boundaries. However, interfaces which meandered along the sample thickness were also sometimes seen.

Microstructure and Josephson Phenomenology in 45º Tilt and Twist YBa2Cu3O7-δ Artificial Grain Boundaries. F.Tafuri, F.M.Granozio, F.Carillo, A.Di Chiara, K.Verbist, G.Van Tendeloo: Physical Review B, 1999, 59[17], 11523-31