الفهرس 
Theoretical Background and LiteratureOnly 14 pages are availabe for public view
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Abstract
An unconventional glass system of the percentage molecular composition (80 <U+2013> x) V2O5 <U+2013> x SrO <U+2013> 20 FeO. (0 <U+2264> x <U+2264> 40). These samples investigated from the structural point of view applying XRD, IR, DTA, density and molar volume. Then the electrical properties as well as switching behavior of these glasses were also investigated. 1) Some alpha Fe2O3 was precipitated in the first two samples. This was shown by both XRD and ME. The detected crystalline phase is not more than about 6% in the 1st sample and decreased directly after that. 2) The addition of SrO act to homogenize the glassy phase and to dissolute the precipitated phase. 3) The IR spectroscopy indicated the presence of many structural groups as VO4, VO3, FeO4, FeO6 as well as many bonds V <U+2013> O <U+2013> V, Fe <U+2013> O <U+2013> V, V=O<U+2026><U+2026>.etc. Also, the nonbridging oxygen decreased gradually with the increase of SrO. 4) The DTA analysis indicated that at moderate and higher SrO content glasses there appear another glassy phase. The calculated glass stability showed gradual increase. 5) The experimental density showed lower values than the calculated ones, while the experimental molar volume showed higher values than those of the empirical ones. This was taken as evidences for the homogeneity of the obtained glassy phase. 6) The dc conductivity values between 2.5 x 1010 and 8 x 103 S.cm1 and the activation energy values are found in between 0.31 and 0.80 eV over the whole temperature range. It can be concluded that the SPH is the dominant conduction mechanism at high temp., but mixed conduction mechanism based on SPH and VRH are dominant at low temperatures. 7) The ac conductivity follow the universal power low and the exponent factor s has found between 0.05 and 0.90 for all glasses and according to the theoretical fitting of the experimental data, it can be concluded that the CBH model is the dominant conduction mechanism in the ac conductivity behavior. 8) The switching phenomenon was observed in the samples that contains SrO between 15 and 40 mole%, but not observed in the first three glasses and this is may be due to the presence crystalline phase . 9) The threshold voltages were found to increase with the increase of SrO and it decreases with the temperatures. The threshold current was found to decrease with the increase of temperature and SrO content in these glasses. The switching activation energies were found to decrease from 0.45 to 0.09 eV as SrO was increased from 15 to 40 mole%.