24 research outputs found
Transport properties of zinc-bismuth oxide glasses
28-32<span style="font-size:11.0pt;line-height:115%;
font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">Zinc-bismuth oxide glasses
of 10-25 mol% of zinc oxide are prepared having thickness between 0.35-0.42 cm
and diameter 0.60-0.95 cm. Physical properties such as density (d), molar volume <span style="font-size:11.0pt;
line-height:115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:arial;mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa;mso-bidi-font-style:="" italic"="">(V),<span style="font-size:11.0pt;line-height:
115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"=""> hopping
distance <span style="font-size:11.0pt;line-height:115%;font-family:
" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa;mso-bidi-font-style:italic"="">(R), number of ions per cc (N) and polaron radius <span style="mso-bidi-font-style:
italic">(rp) are also reported. Polaron radius
is found around 1.85 <span style="font-size:11.0pt;line-height:115%;
font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-theme-font:minor-latin;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">Å<span style="font-size:11.0pt;
line-height:115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">
which shows formation of small polarons. Measurements of de electrical conductivity
are reported in the temperature range 443-573K. - Log σ<span style="font-size:11.0pt;
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versus 1/T and –log µ versus 1/T plots exhibited
linearity. Hopping condition given by Holstein was applied. Polaron band-width (J) satisfies the inequality which shows adiabatic
hopping conduction. The density of Fermi level and the density of localized
states are found to be close to each other.</span
Effect of Past Electric Field on Transport Properties of 8Ov<Sub>2</Sub>O<Sub>5</Sub>-2Op<Sub>2</Sub>O<Sub>5</Sub> Semiconducting Glass
The effect of past electric field on transport properties such as dc-conductivity, activation energy etc. of 8Ov2O5-2Op2O5 semiconducting glass has been considered. The various
parameters N,rp,N (EF) etc. Are calculated from Mou T1/4 analysis, and the results are discussed on the basis of the polaron model
<span style="font-size:11.0pt;line-height:115%; font-family:"Calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family: "Times New Roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font: minor-latin;mso-bidi-font-family:Arial;mso-ansi-language:EN-US;mso-fareast-language: EN-US;mso-bidi-language:AR-SA">Thermal conductivity of V<sub>2</sub>O<sub>5</sub>-P<sub>2</sub>O<sub>5</sub> glasses</span>
291-296<span style="font-size:11.0pt;line-height:115%;
font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">The thermal conductivity of V2O5-P2O5
glass system has been experimentally determined in the temperature range
303-422 K. The data covered the glass composition range from 60 to 80 mol% of V2O5.
It has been observed that the thermal conductivity increases linearly with
temperature. The results obtained confirmed that the major contribution to the
thermal conductivity of this glass system is due to lattice vibrations. The
values of density, molar volume, lattice thermal conductivity (λL)
band gap energy, melting temperature, electronic (λe) and bipolar
component of thermal conductivity (λbp) are also reported.</span
Hopping Conduction Mechanism in Amorphous CuO-BiO Pellets
The transport properties of CuO-BiO pellets (pressed at room temperature 303 K) like dc electrical conductivity etc. are measured. The activation energy, dielectric constant etc. are reported. The hopping conduction is examined. Non-adiabatic hopping conduction is observed. The plot of -log σ versus 1/T is found to be linear. Activation energy of pellets containing CuO (80, 70, 60 mol%) shows electronic conduction while the pellet containing CuO (50 mol%) shows ionic conduction. The effect of content of CuO (mol%) and frequency on dielectric constant is also studied. The variation of dielectric constant with CuO (mol%) shows zigzag nature and may be due to the relaxation effects
<span style="font-size:11.0pt;line-height:115%; font-family:"Calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family: "Times New Roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font: minor-latin;mso-bidi-font-family:Arial;mso-ansi-language:EN-US;mso-fareast-language: EN-US;mso-bidi-language:AR-SA">Effect of pellet pressing temperature on transport properties of amorphous CuO-Bi<sub>2</sub>O<sub>3</sub> pellets</span>
231-235<span style="font-size:11.0pt;line-height:115%;
font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">The results of transport properties of CuO-Bi2O3
pellets pressed at different temperatures are reported. The data of electrical
properties such as dc-electrical conductivity, dielectric constant and
activation energy are discussed. Similarities between CuO-Bi2O3
pellets and oxide glasses are emphasized. New results of pellet pressing
temperature are reported. The hopping conduction phenomenon in three sets of
pellets is discussed. All the three pellets exhibited non-adiabatic electronic
conduction. The results of dc-conductivity are discussed on the basis of
growing of small crystallities in the pellets.</span
<span style="font-size:11.0pt;line-height:115%; font-family:"Calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family: "Times New Roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font: minor-latin;mso-bidi-font-family:"Times New Roman";mso-ansi-language:EN-US; mso-fareast-language:EN-US;mso-bidi-language:AR-SA">Transport properties of amorphous CuO-Bi<sub>2</sub>O<sub>3</sub> semiconducting pellets</span>
33-37<span style="font-size:11.0pt;line-height:115%;
font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The results of measurement
of de-electrical conductivity and activation energy have been reported for four
different composition of CuO-Bi2O3 glass powder pellets
pressed at 50°C in the temperature range of 300 - 493 K. A plot of -log σ<span style="font-size:11.0pt;
line-height:115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:arial;mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"=""> versus 1/T shows two different regions of
conduction suggesting two types of conduction mechanisms switching from one
type to another occurring at Rnee temperature. The de-conductivity increases
with increase in temperature of the sample and also with increase of mol% of
CuO. Activation energy calculated for both regions (LTR and HTR) is below 1 eV,
thus the electrical conduction is electronic. Activation energy decreases with
increase of mol% of CuO. Non-adiabatic hopping conduction was observed in the
sample. A plot of dielectric constant versus log of frequency shows zig-zag
nature. Dielectric constant decreases with increase in mol% of CuO.</span