Growth mechanisms and properties of 90 degrees grain boundaries in YBa2Cu3O7 thin films.

The transport properties of three types of 90 o grain boundaries of (103) oriented YBa 2 Cu 3 O 7 (YBCO) thin films grown epitaxially on (101) SrTiO 3 and (101) LaAlO 3 substrates in situ by 90 o off-axis sputtering are compared. A simple description of the in-plane crystallographic film orientation is given by substrate [010]∥YBCO[010] and substrate [101]∥YBCO . A domain structure exists with the CuO 2 planes oriented at ±45 o to the substrate surface (i.e., parallel to the substrate [010] direction)