ORIENTATION OF Y2BACUO5 PRECIPITATES DURING UNIDIRECTIONAL SOLIDIFICATION OF Y1BA2CU3O7-DELTA UNDER A MAGNETIC-FIELD

The effect of a vertical magnetic field on Y2BaCuO5 (211) precipitates during horizontal unidirectional solidification of YBaCuO has been in vestigated. EPR shows first that some of the residual 211 particles ar e not randomly oriented in the 123 matrix when the sample is processed under a magnetic field. Secondly, the analysis of the angular depende ncy of the EPR spectra shows that these particles tend to be oriented in the 123 crystal with their b(211) crystallographic axis parallel to the applied magnetic field and also to the c(123) axis. X-ray pole fi gures on the same sample lead to an identical conclusion. The conseque nces of this observation regarding YBa2Cu3O7-delta (123) crystallizati on are discussed.