In the presence of rotation, the influences of a lower and a higher ramp rate can be discussed as follows. In the former experiment, rotation imparts symmetry of the solute distribution, diminishes the gradients, the crystal growth rate and results in crystals of better transparency. In the latter, rotation has a less significant role. The solute distribution is homogenized, but there is no improvement in the symmetry of the concentration contours. The crystal growth rates remain high and the solution is density stratified in a shorter period of time. The growth of the crystal is halted at this point. The above discussion shows that for a given ramp rate, a judicious choice of crystal rotation can lead to an enhanced crystal quality, though a slower growth process.

Figure 5.24: (a) Variation of normalized concentration gradients near the three faces of the growing crystal, (b) horizontal growth of the crystal relative to its maximum size as a function of time, and (c) photographs of grown crystals with and without crystal rotation. (Ramp rate= )