Nanoparticles of Nb5+-Fe3+ codoped TiO2 with various Nb5+ concentrations (Nb/(Ti+Fe+Nb)= 0-10.0 at%) and Fe3+ (Fe/(Ti+Fe+Nb)=0-2.0 at%) were synthesized using Ar/O-2 thermal plasma. Dopant content, chemical valence, phase identification, morphology and magnetic properties were determined using several characterization techniques, including inductively coupled plasma-optical emission spectrometer. X-ray photoelectron spectroscopy, X-ray diffraction, UV-vis diffuse reflectance spectrometer, field-emission scanning electron microscopy, transmission electron microscopy and SQUID commercial instrument. The XRD revealed that all the plasma-synthesized powders were exclusively composed of anatase as major phase and rutile. The rutile weight fraction was increased by the substitution of Fe3+ for Ti4+ whereas it was reduced by the Nb5+ doping. The plasma-synthesized Nb5+-Fe3+ codoped TiO2 powders had intrinsic magnetic properties of strongly paramagnetic and feebly ferromagnetic at room temperature. The ferromagnetic properties gradually deteriorated as the Fe3+ concentration was decreased, suggesting that the ferromagnetism was predominated by the phase composition as a carrier-mediated exchange. (C) 2011 Elsevier Inc. All rights reserved.
JAWED, I.;BAILEY, A. E.;RITTER, A. P.;WINZER, S. R., ISAF86: PROC. 6TH IEEE INT. SYMP. APPL. FERROELEC., BETHLEHEM, PA, 8-11 J+
作者:JAWED, I.、BAILEY, A. E.、RITTER, A. P.、WINZER, S. R.
DOI:——
日期:——
Synthesis of Potassium Niobate from Metal Alkoxides
作者:Mostafa M. Amini、Michael D. Sacks
DOI:10.1111/j.1151-2916.1991.tb07296.x
日期:1991.1
Preparation of potassium niobate frommetalalkoxides was investigated. Potassium-niobium ethoxide, KNb(OC2H5)6, and potassium-niobium propoxide, KNb(OC3H7)6, were synthesized and subsequently hydrolyzed using several water concentrations (0.75 to 6.0 mol of water/(mol of alkoxide)). Rapid precipitation of potassium-deficient particles occurred when higher concentrations of water were used. This resulted