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The influences of processing parameters such as mineral-In this work, the hydrothermal synthesis of Y 3 Fe 5 O 12 was izer, temperature, and nonstoichiometry on reaction prodstudied using a nitrate solution of Y and Fe with regard to uct and morphology were investigated in the hydrothermal phase evolution and morphology. The effects of hydrothermal synthesis of yttrium iron garnet, Y 3 Fe 5 O 12 (YIG). A cubic variables such as type of mineralizer, temperature, and nonstoi-YIG phase was synthesized successfully under hydrotherchiometry on the crystallization and powder characteristics mal conditions of 200؇C and 6 h from yttrium and iron were investigated. hydroxide coprecipitates obtained by adjusting the pH to 10.5 using NH 4 OH. The other mineralizer, NaOH, was not II. Experimental Procedure effective in forming the garnet phase. Nonstoichiometric compositions utilizing excess Y content tended to increase A 1M aqueous solution of yttrium and iron nitrates, the yield of the garnet phase, but did not affect the morphol-Y(NO 3 ) 3 и5H 2 O and Fe(NO 3 ) 3 и5H 2 O, as raw materials was preogy. Different morphology characteristics were observed by pared in a Teflon cup. Several nonstoichiometric YIG composichanging the synthesis temperature. Isometric YIG partitions were adjusted by applying excess or deficient Y content. cles disappeared at a relatively high temperature of 250؇C,The compositions are expressed as the atomic ratio between Y resulting in irregular star-shaped particles of YIG due to and Fe in a given composition. For example, the Y/Fe ratio is the preferential orientation during particle growth. 0.6 for stoichiometric Y 3 Fe 5 O 12 . The solution was hydrolyzed by varying the pH value from 7.5 to 11.5 using NH 4 OH or NaOH, resulting in brown coprecipitates. The coprecipitates

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