  Y-Ba-Cu-O (YBCO) and Sm-Ba-Cu-O (SmBCO) thin films have been used for the
first time as heterogeneous seeds to multi-seed successfully the melt growth of
bulk YBCO in a multi-seeded melt growth (MSMG) process. The use of thin film
seeds, which may be prepared with highly controlled orientation (i.e. with a
well-defined a-b plane and precisely known a-direction), is based on their
superheating properties and reduces significantly contamination of the bulk
sample by the seed material. A variety of grain boundaries were obtained by
varying the angle between the seeds. Microstructural studies indicate that the
extent of residual melt deposited at the grain boundary decreases with
increasing grain boundary contact angle. It is established that the growth
front proceeds continuously at the (110)/(110) grain boundary without trapping
liquid, which leads to the formation of a clean grain boundary.
