HYDROTHERMAL PREPARATION AND MORPHOLOGY CHARACTERISTICS OF Y3FE5O12

The influences of processing parameters such as mineralizer, temperatu re, and nonstoichiometry on reaction product and morphology were inves tigated in the hydrothermal synthesis of yttrium iron garnet, Y3Fe5O12 (YIG). A cubic YIG phase was synthesized successfully under hydrother mal conditions of 200 degrees C and 6 h from yttrium and iron hydroxid e coprecipitates obtained by adjusting the pH to 10.5 using NH4OH. The other mineralizer, NaOH, was not effective in forming the garnet phas e, Nonstoichiometric compositions utilizing excess Y content tended to increase the yield of the garnet phase, but did not affect the morpho logy, Different morphology characteristics were observed by changing t he synthesis temperature, Isometric YIG particles disappeared at a rel atively high temperature of 250 degrees C, resulting in irregular star -shaped particles of YIG due to the preferential orientation during pa rticle growth.