Dilute Iron-Doped Yttrium Aluminum Garnets by Mossbauer Spectrometry

CHARACTERIZATION OF DILUTE IRON-DOPED YTTRIUM ALUMINUM GARNETS BY MOSSBAUER SPECTROMETRY 

Mossbauer Spearoscopy Applications in Chemistry, Biology, and Nanotechnology, First Edition. Edited by Virender K. Sharma, Gostar Klingelhdfer, and Tetsuaki Nishida. 

The magnetic phase diagram for diiute ferromagnetic semiconductors. The electrons are localized in the shaded area. Xp and Sp are the cation and donor polaron percolation thresholds, respectively. y is the ratio of the radius of the hydrogenic donor orbital to the Bohr radius [2]. 

The sol-gel method provides uniform fine powders at lower heating temperatures and for shorter heating times than a conventional heating method of mixed oxides. The crystalline sizes of the powders are about 30-50 nm in diameter. X-ray diffraction (XRD) analysis of the prepared YIG and YAG solid solutions revealed garnet structure of A3BSO12 [II] even in the case of Y (AI, Fe) 0 = 4 4 12 starting ratio. In order to investigate where the excess Y atoms are located at, extended X-ray absorption fine structures (EXAFS) were measured. 

Y3Als xFexOi2 (x=0.02, 0.1) and Y3(YAl4 jfFex) 0 2 (x = 0.04, 0.2, 0.4) were prepared by the sol-gel method. First, citric acid and ethylene glycol were added to solutions of Y, Al, and Fe chloride. The mixed solutions with nominal compositions were stirred and evaporated at 353 K, thermally decomposed at 623 K in air, and finally calcined at 1173 K for 3 h in air. 

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