45° Grain Boundary Junctions in (001)-Oriented BiSrCaCuO Films

Abstract
In this study, 45°-rotated [001] tilt boundary junctions were fabricated by controlling the in-plane epitaxy using an MgO seed layer grown on an SrTiO3(001) substrate. The in-plane preferential orientation of the BiSrCaCuO film (2223 composition) grown on the MgO seed layer on the SrTiO3(001) substrate of BiSrCaCuO [100], [010]//MgO[100]//SrTiO3[100] was found using X-ray diffraction. The 45°-rotated [001] tilt boundary junction in the BiSrCaCuO film exhibited RSJ-like behavior. With the use of these junctions, a dc SQUID was fabricated and operated at temperatures up to 65 K.