Synthesis and characterization of some garnet materials using sol-gel processing

In the first part of this study, Ho3Al5O12 garnets were synthesized as undoped and doped with Eu3+, Mn3+, Fe3+ and Cr3+ metal ions in different molar concentrations of 0.10, 0.25, 0.50, 0.75, 1.00 by sol-gel technique. In the second part, the synthesis of undoped and doped with Eu3+ ion Dy3Al5O12 and Tb3Al5O12 garnets was succesfully done through sol-gel process using with 1,2 ethanediol as complexing agent. The two different heat conditions as 800˚C and 1000˚C were applied to the obtained gels for all products. In spite of heating at 800°C was not suitable temperature for the products, the reactions are monitored by sampling after 800˚C. However, all of these products showed that a single phase which has been occured at 1000˚C. The FTIR analysis indicated that the organic residues have flown after 10 hours and the typical vibrational bands of M-O bonds have been seen under 1000cm-1 for all products. The XRD patterns showed similar hkl values belong to the typical cubic garnet structures and the doping of the metal ions did not cause any change in the crystal structure of the monophasic host garnet materials. The products were found thermodynamically stable upon 900oC by analyzing TG/DTA curves. The SEM studies showed that the lanthanide aluminum garnets were in the same plate-like shape, independently the nature of the lanthanides or doping agents of Eu3+, Cr3+, Mn3+, Fe3+. The presence of dopants was confirmed by EDX anaylsis. The optical properties of all products were determined by UV-vis/DRS technique.