THE DEPENDENCE OF CE INCORPORATION ON THE EFFECTIVE DISTRIBUTION COEFFICIENT OF CE IN ND2-XCEXCUO4 SINGLE-CRYSTALS GROWN BY THE TSFZ METHOD

Nd2-xCexCuO4 crystals have been grown by the TSFZ process at an oxygen partial pressure in the growth atmosphere of about 2.0, 0.2 and 0.1 a tm. The corresponding values of the cerium effective distribution coef ficient are 9.1, 3.4 and 2.4. It has been found that the Ce concentrat ion in the central part of the crystals is slightly lower than that in the peripheral part, although the average Ce concentration has the sa me value as that in the feed rods. This phenomenon is discussed from t he point of view of the different stirring conditions in the correspon ding parts of the molten zone. The difference in the Ce concentration between the central and peripheral parts of the crystals becomes lower at decreased oxygen partial pressure in the growth atmosphere. Optimi zation of the growth conditions at the air atmosphere (oxygen partial pressure 0.2 atm) is pointed out as the promising way for quality impr ovement of the Nd2-xCexCuO4 single crystals.