Possibilities and limitations of multioxides crystals growth

摘要

The main methods of crystal growth from the melt the Czochralski and floating zone will be discussed and compared. Advantages, disadvantages and limitations of both methods as well as ways of solving some of the problems existing during growth of different types of multioxides crystals will be discussed. The chemical composition of crystals grown by the Czochralski method very often differs from the stoichiometric composition. Such deviations were found and well documented in a few groups of materials for example in garnets. Since the deviation is not known for most of the crystals, a simple way to determine the optimum starting composition of the melt will be presented. In order to determine the composition of the melt one should take into account evaporation of a volatile component that dissociates at high temperatures during crystal growth. Some problems related to the dopant distribution along the crystal growth direction in correlation with segregation coefficient for both methods will be discussed. To grow solid solution single crystals by the Czochralski method with a desired concentration of the admixture one has to know segregation coefficients of the components. A few examples of the dopant solubility limit in different crystal matrices will be presented.