The kinetic growth anisotropy of the 123-(RE)BaCuO compounds

The kinetic growth anisotropy of the melt-textured 123-(RE)BaCuO compounds, especially along the CuCO2 planes, is discussed here in detail. A computer model which simulates the grain growth of 123 materials in the ab plane is presented. This kinetic growth model takes some bond anisotropy along the [100] and [110] directions into account. The model presented herein belongs to a hierarchical set of generalized Eden models as discussed in the Appendix. For different bond anisotropy parameters, the simulated 123-(RE)BaCUO grains exhibit square and octogonal overall shape which have been both optically observed. From simple kinetic arguments, we show that the 'faceting' of the 123-(RE)BaCuO grains finds its origin in a bond anisotropy rather than in a growth-rate anisotropy along some crystallographic directions. This is of general interest and opens new perspectives for developing the Eden model in the crystal-growth field.