Controlled grain boundaries between a-axis and c-axis films were prepared. By selectively depositing c-axis and in-plane aligned a-axis material onto the same substrate, it was possible to grow nominally 90 [010] basal plane-faced tilt and twist grain boundaries onto LaSrGaO4 substrates. It was found that the twist grain boundary was very robust and exhibited a high critical current density and a weak field dependence. It was as well-coupled as the present [010] antiphase boundaries. The basal plane-faced tilt boundary was not as strong, but it coupled better than high-angle [001] tilt grain boundaries in c-axis films. Although the basal plane-faced tilt boundaries limited the critical current density, they did not reduce it by more than an order of magnitude and the field dependence was very weak. The grain boundaries were considered in terms of weak links.

D.J.Lew, Y.Suzuki, A.F.Marshall, T.H.Geballe, M.R.Beasley: Applied Physics Letters, 1994, 65[12], 1584-6