THE KINETIC GROWTH ANISOTROPY OF THE 123-(RE)BACUO COMPOUNDS

The kinetic growth anisotropy of the melt-textured 123-(RE)BaCuO compo unds, especially along the CuO2 planes, is discussed here in detail. A computer model which simulates the grain growth of 123 materials in t he ab plane is presented. This kinetic growth model takes some bond an isotropy along the [100] and [110] directions into account. The model presented herein belongs to a hierarchical set of generalized Eden mod els as discussed in the Appendix. For different bond anisotropy parame ters, the simulated 123-(RE)BaCuO grains exhibit square and octagonal overall shape which have been both optically observed. From simple kin etic arguments, we show that the 'faceting' of the 123-(RE)BaCuO grain s finds its origin in a bond anisotropy rather than in a growth-rate a nisotropy along some crystallographic directions. This is of general i nterest and opens new perspectives for developing the Eden model in th e crystal-growth field.