ISSN:
0741-0581
Schlagwort(e):
Ferrites
;
Se
;
Random system
;
Amorphous
;
Spin-glass
;
Polar-glass
;
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Allgemeine Naturwissenschaft
Notizen:
The structure of amorphous Se films, in the topological random system, has been studied by the computer-simulation, electron diffraction (ED), and high-resolution transmission electron microscopy (HRTEM). As an example of HRTEM of the cellular random system, our recent investigation on Ba-ferrites is reviewed beforehand. In HRTEM images of spin-glass BaTi2-xSnxFe4O11 (x 〈 0.6), magnetic clusters or clusters of FeO6-octahedra surrounded by TiO6-octahedra have been found. The structure of BaSn2Fe4O11 (x = 2) has been determined. The ordering of Sn (Ti) and Fe ions increases with increasing x, which interprets the change from the spin-glass state to nonspin-glass state at x = 0.6. It is shown that a cluster of polarized lattice ions is detectable in images of polar-glass BaxK2-xFexTi6-xO13 (x ≥ 1.2). The structure models of amorphous Se films forming on a substrate have been constructed on a computer, and their radial distribution function (RDF) and HRTEM images have been calculated. Experimental RDF and HRTEM images have been obtained from vacuum-deposited amorphous Se films and are compared with the calculated ones. It is concluded that in the as-deposited films most of Se molecules may be composed of Se atoms as small as three and that by the electron-beam irradiation the molecules link to form spiral chains in amorphous state and then arrange to have the hexagonal crystal structure.
Zusätzliches Material:
18 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jemt.1060120311
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