NEW REAGENTS FOR THE CHEMICAL SYNTHESIS OF FINE RARE-EARTH ORTHOFERRITE POWDERS

Citation
A. Pathak et al., NEW REAGENTS FOR THE CHEMICAL SYNTHESIS OF FINE RARE-EARTH ORTHOFERRITE POWDERS, Nanostructured materials, 8(1), 1997, pp. 101-117
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Material Science
Journal title
ISSN journal
0965-9773
Volume
8
Issue
1
Year of publication
1997
Pages
101 - 117
Database
ISI
SICI code
0965-9773(1997)8:1<101:NRFTCS>2.0.ZU;2-0
Abstract
Ultrafine (less than or equal to 150 nm) rare-earth orthoferrites (RFe O(3) where R = Sm, Nd, and Gd) with good purity and chemical homogenei ty were prepared through two solution-based chemical routes using some new and versatile chemical reagents. The first route involved copreci pitation of mixed metal nitrates from their aqueous solutions, in the presence of water soluble polyvinyl alcohol (PVA), using triethylammon ium carbonate solution. The other process involved complete evaporatio n of a mixture of optimum amounts of PVA and the desired aqueous metal nitrate solutions, with the addition of the optimum amount of urea wh en the mixture was evaporated to a pasty mass. In addition, detailed s tudy of the reported potassium ferricyanide route was also carried out for the production of the same powders. The precursor as well as the heat-treated RFeO(3) powders, prepared through these three routes, wer e compared by physical characterization studies involving thermal grav imetry and differential scanning calorimetry (TG/ DSC), Infrared spect roscopy (IR), X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM), and room temperature magnetic measurements.