A new method was developed for the preparation of bicrystals with well-defined planar interfaces. The misorientation of the bi-crystal was controlled by means of dual seeding, using Cu3Ba2NdO7 monocrystals. The grain boundary plane orientation was affected by the position of the seeds and by the temperature gradient. Macro-, meso- and microscopic planarity of the grain boundaries was established by means of optical and electron microscopy. A difference of almost 2 orders of magnitude of critical current density was found between low-angle (less than 10) and high-angle (greater than 20) misorientations. This was established by studying a series of [001]-tilt grain boundaries. It was concluded that this type of grain boundary could permit a less ambiguous interpretation to be made, of the relationship between microstructure and transport properties, than was possible by using bi-crystalline thin-film boundaries. This resulted from the elimination of potential variations in properties that were associated with a varying grain boundary plane.

V.R.Todt, X.F.Zhang, D.J.Miller, M.S.Louis-Weber, V.P.Dravid: Applied Physics Letters, 1996, 69[24], 3746-8