SUBSTITUTED IRON OXIDES FOR THE GRANT ENTITLED LASER PROCESSING OF ADVANCED MAGNETIC MATERIALS

Sorescu, Monica

Duquesne University (United States)

关键词: Interstitials;    Dimensions;    X-Ray Diffraction;    Processing;    Magnetic Materials;   

DOI  :  10.2172/822034
RP-ID  :  NONE
RP-ID  :  FG26-02NT41595
RP-ID  :  822034

美国|英语

来源: UNT Digital Library

【 摘 要 】

Structural and morphological characteristics of (1-x){alpha}-Fe{sub 2}O{sub 3}-xSnO{sub 2} (x = 0.0-1.0) nanoparticles obtained under hydrothermal conditions have been investigated by X-ray diffraction (XRD), transmission Moessbauer spectroscopy, scanning (SEM) and transmission electron microscopy (TEM) as well as energy dispersive X-ray analysis (EDX). On the basis of the Rietveld structure refinements of the XRD spectra at low tin concentrations, it was found that Sn{sup 4+} ions partially substitute for Fe{sup 3+} at the octahedral sites and also occupy the interstitial octahedral sites which are vacant in {alpha}-Fe{sub 2}O{sub 3} corundum structure. A phase separation of {alpha}-Fe{sub 2}O{sub 3} and SnO{sub 2} was observed for x {ge} 0.4: the {alpha}-Fe{sub 2}O{sub 3} structure containing tin decreases simultaneously with the increase of the SnO{sub 2} phase containing substitutional iron ions. The mean particle dimension decreases from 70 nm to 6 nm, as the molar fraction x increases up to x = 1.0. The estimated solubility limits in the nanoparticle system (1-x){alpha}-Fe{sub 2}O{sub 3}-xSnO{sub 2} synthesized under hydrothermal conditions are: x {le} 0.2 for Sn{sup 4+} in {alpha}-Fe{sub 2}O{sub 3} and x {ge} 0.7 for Fe{sup 3+} in SnO{sub 2}. These findings are in press in the Journal of Physics and Chemistry of Solids.