Sol-gel processing of electrical and magnetic ceramics

Influence of synthesis procedure on the YIG formation

Polycrystalline Y3Fe5O12 (YIG) and Y3Al5O12 (YAG) garnets have been prepared by the organic solution technique using a novel organic precursor. The thermal decomposition of the precursor and subsequent formation of the garnet phases was studied by thermal analysis, X-ray diffraction and Fourier transform infra red spectroscopy (FTIR) including diffuse reflectance FTIR (DRIFT). The precursor of YIG decomposes to give the garnet phase as the main component at 800 °C. YFeO3 and Fe2O3 are also present, and react to give YIG at higher temperatures. Single-phase YAG can be obtained from its precursor at 1100 °C. The reaction proceeds via a hexagonal YAlO3 intermediate which is formed at 850 °C.

Synthesis of polycrystalline yttrium iron garnet and yttrium aluminium garnet from organic precursors

http://cmdmc.com.br/redecmdmc/lab/arquivos_publicacoes/271_Camargo2002SolidStateIonics.pdf

Low temperature synthesis of lithium niobate powders based on water-soluble niobium malato complexes

Bimetallic alkoxides of niobium

Crystalline LiNbO3 was prepared by simultaneous hydrolysis of lithium and niobium alkoxides (in the mole ratio Li : Nb = 1 :1) followed by heat treatment. Crystallization of LiNbO3 occurs in a wide temperature region, 350 to 700° C, directly from an amorphous hydrolysis product containing residual alkoxy and hydroxy groups. Heat treatment at 700° C results in the formation of fully crystalline LiNbO3 powder with completely formed ferroelectric properties. Hydrolysis of metal alkoxide solutions is successfully used to obtain high-quality LiNbO3 crystalline thin films.

N. V. Kolganova

Papers

Formation of LiNbO3 powders and thin films by hydrolysis of metal alkoxides

Alkoxy-derived oxide phases of the system Fe2O3-Y2O3