Electric conductivity of glasses in the system Na2O/CaO/SiO2/Fe2O3

Harizanova, Ruzha; Keding, Ralf; Rüssel, Christian

doi:10.1016/j.jnoncrysol.2007.07.014

Cited by 16 publications

(10 citation statements)

References 25 publications

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“…At high concentration, iron-containing glasses behave as amorphous semiconductors [56,57]. Mixed valence conduction in these glasses is described in terms of electronhopping between neighboring Fe 3+ and Fe 2+ [56,58].…”

Section: Influence Of Iron Clustering On Physical Propertiesmentioning

confidence: 99%

Nature and distribution of iron sites in a sodium silicate glass investigated by neutron diffraction and EPSR simulation

Weigel

Cormier

Calas

et al. 2008

Journal of Non-Crystalline Solids

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a b s t r a c tThe short and medium range structure of a NaFeSi 2 O 6 (NFS) glass has been investigated by high-resolution neutron diffraction with Fe isotopic substitution, combined with Empirical Potential Structure Refinement (EPSR) simulations. The majority ($60%) of Fe is 4-coordinated ( [4] Fe) and corresponds only to ferric iron, Fe 3+ , with a distance d½4 Fe 3þ ÀO ¼ 1:87 AE 0:01 Å. This is at variance with the 3D-structure predicted by glass stoichiometry. The existence of a majority of [4] Fe 3+ sites illustrates a glass structure that differs from the structure of crystalline NaFeSi 2 O 6 , which contains only octahedral Fe 3+ . The EPSR modeling of glass structure shows that [4] Fe 3+ is randomly distributed in the silicate network and shares corner with silicate tetrahedra. The network-forming behavior of [4] Fe 3+ , coupled with the presence of Na + ions acting as charge-compensators, is at the origin of peculiar physical properties of Fe-bearing glasses, such as the increase of the elastic modulus of sodium silicate glasses with increasing Fe-concentration. Our data provide also direct evidence for 5-coordinated Fe, with an average distance d½5 FeÀO ¼ 2:01 AE 0:01 Å. This second Fe population concerns both Fe 2+ and Fe 3+ . 5-Coordinated Fe atoms tend to segregate by sharing mainly edges. The direct structural evidence of the dual role of ferric iron in NFS glass provides support for understanding the peculiar properties of NFS glass, such as magnetic, optical, electronic or thermodynamic properties.

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Section: Influence Of Iron Clustering On Physical Propertiesmentioning

confidence: 99%

Nature and distribution of iron sites in a sodium silicate glass investigated by neutron diffraction and EPSR simulation

Weigel

Cormier

Calas

et al. 2008

Journal of Non-Crystalline Solids

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“…Glasses with a high concentration of polyvalent transition metal ions exhibit semiconducting electrical properties. [1][2][3][4][5] For example, glasses based on soda-lime glasses with Fe 2 O 3 -concentrations in the range from 5 to 30 mol% show an increase in the electric conductivity with increasing transition metal concentration. The crystallisation of semiconducting phases from these glasses may further increase the electrical conductivity.…”

Section: Introductionmentioning

confidence: 99%

“…The crystallisation of semiconducting phases from these glasses may further increase the electrical conductivity. [5][6][7][8] In glasses with more than 20 mol% Fe 2 O 3 a notable increase in conductivity is observed 5 during crystallisation which has mainly been attributed to the formation of magnetite. The latter is e.g.…”

Section: Introductionmentioning

confidence: 99%

“…10 The crystallisation of magnetite may lead to the formation of interconnected semiconducting crystals which leads to a strong increase in the electric conductivity. 5 It was further reported that electrons are the main charge carriers and the conduction mechanism was described as a non-adiabatic, thermally activated hopping of small polarons. 5 The occurrence of both magnetite and hematite within the same crystals in glass-ceramics was previously reported in one of the first publications applying electron backscatter diffraction (EBSD) to glass-ceramics.…”

Section: Introductionmentioning

confidence: 99%

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Crystallisation of iron containing glass–ceramics and the transformation of hematite to magnetite

et al. 2011

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“…Lubas et al [11] studied by IR some glasses prepared mainly from basalt and found that these samples have high crystallization capability when heat treated. Many other articles have been published concerned with the study of various glasses with composition similar to that of the present samples [12][13][14].…”

Section: Introductionmentioning

confidence: 87%

Structural Study of Glass and Glass Ceramics Prepared with Egyptian Basalt

Hassaan

Saudi

Saad

et al. 2015

Silicon

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Egyptian basalt rock was used to prepare some glasses with different additives of Na 2 O by the melt quenching method. The prepared glasses were characterized applying FTIR, XRD and Mössbauer Effect (ME) spectroscopy. XRD indicated that all the samples showed a homogeneous glassy phase except the sample containing 35 mol % of Na 2 O which showed a very small crystalline phase of less than 5 %. FTIR measurements indicated the presence of various structural units including SiO 4, FeO 4 and AlO 4 . ME hyperfine parameters indicated the presence of both Fe 2+ and Fe 3+ in the low Na 2 O content glasses (the first three samples), while the iron in the high Na 2 O content glasses (the last three samples) showed only the Fe 3+ state. All the glass samples were heated at 900 • C for 6 h, of which XRD analysis showed different crystallites of nanometer size. ME spectra of the heat-treated (HT) samples indicated the presence of magnesium ferrites as confirmed by XRD study.

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Electric conductivity of glasses in the system Na2O/CaO/SiO2/Fe2O3

Cited by 16 publications

References 25 publications

Nature and distribution of iron sites in a sodium silicate glass investigated by neutron diffraction and EPSR simulation

Nature and distribution of iron sites in a sodium silicate glass investigated by neutron diffraction and EPSR simulation

Crystallisation of iron containing glass–ceramics and the transformation of hematite to magnetite

Structural Study of Glass and Glass Ceramics Prepared with Egyptian Basalt

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