STRUCTURE AND ELECTRICAL PROPERTIES OF SrO-BOROVANADATE (V2O5)z(SrO)0.2(B2O3)0.8-z GLASSES

2010 ◽  
Vol 24 (11) ◽  
pp. 1471-1488
Author(s):  
A. MEKKI ◽  
G. D. KHATTAK ◽  
M. N. SIDDIQUI
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Inductively Coupled Plasma ◽  
Glass Structure ◽  
Model Parameters ◽  
Nominal Composition ◽  
Polaron Hopping ◽  
X Ray ◽  
Dc Electrical Conductivity ◽  
Hopping Model

SrO -borovanadate glasses with the nominal composition (V 2 O 5 ) z( SrO )0.2 ( B2 O 3 ) 0.8-z, 0.4≤z ≤0.8 were studied by direct current (DC) electrical conductivity, inductively coupled plasma (ICP) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and X-ray-powder-diffraction (XRD). These glasses were prepared by a normal quench technique and the actual compositions of the glasses were determined by ICP spectroscopy. XRD patterns confirm the amorphous nature of the present glasses. The temperature dependence of DC electrical conductivity of these glasses has been studied in terms of different hopping models. The IR results agree with previous investigations on similar glasses and it has been concluded that similar to SrO -vanadate glasses, metavandate chainlike structures of SrV 2 O 6 and individual VO 4 units also occur in these SrO -borovanadate glasses. The SrV 2 O 6 and VO n polyhedra predominate in the low B 2 O 3 containing SrO -borovanadate glasses as the B substitutes into the V sites of the various VO n polyhedra and only when the B 2 O 3 concentration exceeds the SrO content do BO n structures appear. This qualitative picture of three distinct structural groupings for the Sr -vanadate and Sr -borovanadate glasses is consistent with the proposed glass structure on previous IR and extended X-ray absorption fine structure (EXAFS) studies on these types of glasses. The conductivity results were analyzed with reference to theoretical models existing in the literature and the analysis shows that the conductivity data are consistent with Mott's nearest neighbor hopping model. However, both Mott VRH and Greaves models are suitable to explain the data. Schnakenberg's generalized polaron hopping model is also consistent with the temperature dependence of the activation energy, but the various model parameters such as density of states, hopping energy obtained from the best fits were found to be not in accordance with the prediction of the Mott model.

Durability studies of simulated UK high level waste glass

2014 ◽  
Vol 1665 ◽  
pp. 291-296
Author(s):  
Nor E. Ahmad ◽  
Julian R. Jones ◽  
William E. Lee
Keyword(s):  
Inductively Coupled Plasma ◽  
Glass Structure ◽  
Ruthenium Oxide ◽  
Optical Emission ◽  
High Level Waste ◽  
Corrosion Mechanism ◽  
Aqueous Corrosion ◽  
Static Mode ◽  
X Ray ◽  
High Level

ABSTRACTA simulated Magnox glass which is Mg- and Al- rich was subjected to aqueous corrosion in static mode with deionised water at 90 °C for 7-28 days and assessed using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy X-Ray Dispersive Spectroscopy (EDS) and Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES). XRD revealed both amorphous phase and crystals in the glass structure. The crystals were Ni and Cr rich spinels and ruthenium oxide. After two weeks of incubation in deionised water, the glass surface was covered by a ∼11 μm thick Si-rich layer whilst mobile elements and transition metals like Na, B, and Fe were strongly depleted. The likely corrosion mechanism and in particular the role of Mg and Al in the glass structure are discussed.

CRYSTAL STRUCTURE, ELECTRICAL CONDUCTIVITY AND THERMAL EXPANSION OF Pr1-xSrxFeO3-δ(0 ≤ x ≤ 0.6)

2012 ◽  
Vol 26 (32) ◽  
pp. 1250174 ◽  
Author(s):  
V. PRASHANTH KUMAR ◽  
Y. S. REDDY ◽  
P. KISTAIAH ◽  
C. VISHNUVARDHAN REDDY
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Room Temperature ◽  
Small Polaron ◽  
Linear Thermal Expansion ◽  
Lattice Parameter ◽  
Polaron Hopping ◽  
X Ray ◽  
Perovskite Type

The crystal structure at room temperature (RT), thermal expansion from RT to 1000°C and electrical conductivity, from RT to 600°C, of the perovskite-type oxides in the system Pr 1-x Sr x FeO 3(x = 0, 0.2, 0.4, 0.6) were studied. All the compounds have the orthorhombic perovskite GdFeO 3-type structure with space group Pbnm. The lattice parameters were determined by X-ray powder diffraction. The Pseudo cubic lattice parameter decreases with an increase in x, while the coefficient of linear thermal expansion increases. The thermal expansion is almost linear for x = 0 and 0.2. The electrical conductivity increases with increasing x while the activation energy decreases. The electrical conductivity can be described by the small polaron hopping conductivity model.

X-ray diffraction studies and DC electrical conductivity of poly(2-halogenanilines) and their composites with polyfuran

2005 ◽  
Vol 59 (1) ◽  
pp. 80-84 ◽  
Author(s):  
Ayşegül Gök ◽  
Hatice Kaplan Can ◽  
Bekir Sarı ◽  
Muzaffer Talu
Keyword(s):  
Electrical Conductivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dc Electrical Conductivity

Synthesis and processing of nanocrystalline Ag–Fe–Ni for low thermal expansion–high conductivity thermal management applications

2001 ◽  
Vol 16 (2) ◽  
pp. 340-343 ◽  
Author(s):  
J. Stolk ◽  
M. Gross ◽  
D. Stolk ◽  
A. Manthiram
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Metal Ion ◽  
Coefficient Of Thermal Expansion ◽  
Thermomechanical Analysis ◽  
Nominal Composition ◽  
Two Phase ◽  
X Ray ◽  
Fine Grained ◽  
Low Thermal Expansion

Nanocrystalline Ag–Fe–Ni powders were produced by a reduction of the aqueous metal ion solutions with sodium borohydride and then converted to fine-grained silver–Invar alloys that offer attractive thermal, electrical, and mechanical properties. The samples were characterized by x-ray diffraction, scanning electron microscopy, wavelength dispersive x-ray spectrometry, thermomechanical analysis, microhardness measurements, and electrical conductivity measurements; thermal conductivity was estimated using the Wiedemann–Franz law. Sintering of a specimen with a nominal composition of 60 wt% Ag–25.6 wt% Fe–14.4 wt.% Ni led to the formation of a two-phase silver–Invar alloy with a grain size of approximately 2 μm, a hardness of 133 HK200g, coefficient of thermal expansion of 12.44 × 10−6 / °C, and electrical conductivity of 2.13 × 105 (Ω cm) −1.

Optical and Electrical Properties of Ion Beam Effects in Ge10Se70Bi20 Thin Films

2021 ◽  
Author(s):  
M Abdelhamid ◽  
A Abdel Reheem ◽  
N Kassem ◽  
A Ashour
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Data Storage ◽  
Ion Beam ◽  
Optical Data Storage ◽  
Optical Measurements ◽  
Optical Data ◽  
X Ray ◽  
Glass Substrates ◽  
Dc Electrical Conductivity

Abstract In this study, chalcogenide material Ge 10 Se 70 Bi 20 thin films have been fabricated utilizing the thermal evaporation technique of bulk samples on glass substrates. After that, the original Ge 10 Se 70 Bi 20 thin films irradiated by different types of an ion beam. The compositions of the original film was determined by the Energy Dispersive X-Ray (EDX). X-ray diffraction (XRD) measurements were performed to characterize and examine the induced variations in the structure of Ge 10 Se 70 Bi 20 films after irradiation. From the optical measurements, the absorption edge, bandgap, Urbach energy, Tauc parameter, and extinction coefficient of the unirradiated and irradiated films were determined. In particular, the DC electrical conductivity increased by two orders after the pure film was exposed to an oxygen ion beam. Besides, the activation energy and Mott’s parameters for the original and irradiated Ge 10 Se 70 Bi 20 films were deduced. The reported variations in absorption coefficient, optical bandgap, dc electrical conductivity, and Mott’s parameters propose that the irradiated Ge 10 Se 70 B 20 thin films can be used in important applications, e.g., optical data storage and optoelectronic devices.

scholarly journals Dc electrical properties of semiconducting cobalt oxide substituted lead vanadate glasses

2018 ◽  
Vol 7 (4.5) ◽  
pp. 625
Author(s):  
K. K. Brahmananda Rao ◽  
K. V. Ramesh ◽  
P. Tejeswara Rao
Keyword(s):  
Electrical Conductivity ◽  
Present System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dc Electrical Conductivity ◽  
Amorphous Nature ◽  
Lead Vanadate ◽  
Vanadate Glasses ◽  
Dc Electrical Properties

Semiconducting lead vanadate glasses with CoO substitution represented as xCoO-(50-x) PbO-50V2O5 with x=5,10 and 15 mol% were prepared by melt quenching technique. They were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), differential thermal analysis (DTA) and DC electrical conductivity. The overall features of these XRD curves reveal the amorphous nature of present glasses. SEM investigations were conducted for the micro structural characterization of V2O5 crystal phases. Density was observed to decrease with an increase in CoO content. The dc electrical conductivity of the present system increases as the concentration of substitution of CoO increases with 5molpercentage to 15molpercentage.  

Transport properties and the structure of vanadium phosphate glasses

1977 ◽  
Vol 55 (5) ◽  
pp. 436-441 ◽  
Author(s):  
B. D. Jordan ◽  
C. Calvo
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Composition Range ◽  
Phosphate Glasses ◽  
Vanadium Phosphate ◽  
Jump Frequency ◽  
X Ray ◽  
Concentration Variable ◽  
Hopping Model ◽  
Vanadium Ion

The adiabatic hopping model for the electrical conductivity of the vanadium phosphate glasses, V1+xP1−xO5−c/2, is examined in terms of their structures as derived from recent X-ray studies. These indicate that the relevant concentration variable for rationalizing the Seebeck coefficient data is c, the fraction of non-tetrahedral vanadium ion sites which are polarons. The polarons interlayer coordination number is 3. The average hopping distance varies by only 5% for 0 ≤ x ≤ 1. The experimental conductivities compared with[Formula: see text]suggest that n is near 3 and that the jump frequency v0 varies by nearly a factor of 3 over the composition range.

scholarly journals DC conductivity and Seebeck coefficient of nonstoichiometric MgCuZn ferrites

2017 ◽  
Vol 35 (1) ◽  
pp. 40-44 ◽  
Author(s):  
W. Madhuri ◽  
S. Roopas Kiran ◽  
M. Penchal Reddy ◽  
N. Ramamanohar Reddy ◽  
K.V. Siva Kumar
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Small Polaron ◽  
X Ray Diffraction ◽  
High Definition ◽  
Conventional Solid State Reaction ◽  
Polaron Hopping ◽  
Dc Electrical Conductivity ◽  
Phase Spinel ◽  
Diffraction Patterns

AbstractNonstoichiometric series of Mg0.5−xCuxZn0.5Fe1.9O4−δ where x = 0.0, 0.1, 0.15, 0.2 and 0.25 has been synthesized by conventional solid state reaction route. The single phase spinel structure of the double sintered ferrites was confirmed by X-ray diffraction patterns (XRD). The ferrite series was studied in terms of DC electrical conductivity and thermoelectric power in the temperature ranging from room temperature to 300 °C and 400 °C, respectively. It was observed that DC electrical conductivity and Seebeck coefficient α decreased with the increase in x. DC electrical conductivity was found to decrease by about 4 orders. All the compositions showed a negative Seebeck coefficient exhibiting n-type semiconducting nature. From the above experimental results, activation energy and mobility of all the samples were estimated. Small polaron hopping conduction mechanism was suggested for the series of ferrites. Owing to their low conductivity the nonstoichiometric MgCuZn ferrites are the best materials for transformer core and high definition television deflection yokes.

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