Crystallization kinetics of Nd-substituted yttrium iron garnet prepared through sol-gel auto-combustion method

Nd substituted Y3Fe5O12 (YIG) was synthesized using sol-gel auto-combustion method. The phases present in the samples were identified using XRD. The asprepared dried gel was found to transform to the rare earth iron garnet phase at lower temperature when the Nd concentration is lower. Higher concentration of Nd resulted in the formation of orthoferrite as the major phase. The Curie temperature was recorded using thermomagnetic analysis and it was found to increase with the concentration of Nd. The crystallization kinetics of the Nd-substituted garnet phase was studied using TG-DTA. Two stage crystallization was observed from the DTA analysis for Nd1Y2Fe5O12. The activation energy for the formation of Nd1Y2Fe5O12 was 610 kJ/mol, found by using Johnson-Mehl-Avrami (JMA) equation. Three dimensional growth mechanism dominate at lower heating rates for the Nd-substituted YIG. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.