Electrical Conductivity and Nonstoichiometry in Pr0.545Ce0.455O2-x

1996 ◽  
Vol 453 ◽  
Author(s):  
O. Porat ◽  
H. L. Tuller ◽  
M. Shelef ◽  
E. M. Logothetis
Keyword(s):  
Electrical Conductivity ◽  
Phase Separation ◽  
Solid State ◽  
Small Polaron ◽  
Coulometric Titration ◽  
Oxygen Nonstoichiometry ◽  
Conductivity Measurements ◽  
Two Phase ◽  
Polaron Hopping ◽  
P Type

AbstractThe oxygen nonstoichiometry of Pr0.545Ce0.455O2-x was studied by solid state coulometric titration and was found to be extensive (0 ≤ y ≤ 0.28) at temperatures of 400–600 °C. The Po2 - x curves showed evidence of the existence of a number of single and two phase regions. Electrical conductivity measurements, performed under similar conditions, exhibited a p-n transition for temperature of 500 °C and below. The activated p-type conductivity was modeled in terms of the small polaron hopping mechanism. The p-n transition was correlated with the onset of phase separation.

Synthesis and Characterization of the Cathode Materials La0.7Sr0.15Ca0.15Co1-yFeyO3-δ for ITSOFC

2010 ◽  
Vol 105-106 ◽  
pp. 653-656
Author(s):  
W.Y. Gao ◽  
Z.Q. Hu ◽  
X.G. Sui ◽  
C.M. Li ◽  
N.L. Tang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Cathode Materials ◽  
Raw Materials ◽  
Small Polaron ◽  
Polaron Hopping ◽  
Metal Nitrates ◽  
Conducting Mechanism ◽  
A Site ◽  
P Type

La0.7Sr0.15Ca0.15Co1-yFeyO3-δ(LSCCF)powders with 0.2y0.5 for the applications as the cathode materials in intermediate temperature solid oxide fuel cell(ITSOFC) were synthesized by glycine-nitrates-process(GNP) using metal-nitrates and glycine as the raw materials. The process, crystal structure and particles morphology of the powders calcined at 600°C,800°C,1000°C for 3h were characterized by IR,XRD and SEM. The experimental results show that co-doped Ca2+ and Sr2+ replacing some La3+ in A site and Fe3+ replacing some Co3+ in B site didn’t influence the formation of perovskite structure and the powders calcined at 800°C for 3h were high pure single perovskite state. The electrical conductivity of LSCCF samples sintered at 1200°C for 3h,was measured as a function of temperature from 100°C to 800°C by the four-probe DC method in air.As a result, the conducting mechanism of LSCCF is p-type small polaron hopping process, and the electrical conductivity are all higher than 100 S/cm. But the electrical conductivity of LSCCF samples increase with Fe3+ content decrease.

Synthesis of New Chalcogenide Materials. The Novel One-Dimensional Semiconductor K4 Ti3 S14

1987 ◽  
Vol 97 ◽  
Author(s):  
Steven A. Sunshine ◽  
Doris Kang ◽  
James A. Ibers
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Alkali Metal ◽  
The Novel ◽  
Conductivity Measurements ◽  
One Dimensional ◽  
General Utility ◽  
Solid State Materials ◽  
Chalcogenide Materials

ABSTRACTThe use of A2 Q/Q melts (A - alkali metal, Q - S or Se) for the synthesis of new one-dimensional solid-state materials is found to be of general utility and is illustrated here for the synthesis of K4 Ti3 SI4. Reaction of Ti metal with a K2 S/S melt at 375°C for 50 h affords K4 Ti3 SI4. The structure possesses one-dimensional chains of seven and eightcoordinate Ti atoms with each chain isolated from all others by surrounding K atoms. There are six S-S pairs (dave - 2.069(3) Å) so that the compound is one of TiIV and may be described as K4 [Ti3 (S)2 (S2)6]. Electrical conductivity measurements indicate that this material is a semiconductor.

Studies on metal hydroxy compounds. XV. Electrical conductivity measurements on Cd(OH)Cl, Cu(OH)Cl, and PbOHCl

1977 ◽  
Vol 55 (19) ◽  
pp. 3377-3379
Author(s):  
Mahadeva Natarajan ◽  
Etalo A. Secco
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Temperature Measurements ◽  
Conductivity Measurements ◽  
Decomposition Step ◽  
Hydroxy Compounds

The electrical conductivity dependence on temperature measurements for three metal basic chlorides are reported. The conductivity results yield energy values which are interpreted in terms of active solid state processes leading up to, and including, the decomposition step.

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.

Characterization of Cathode Materials Ln0.7Sr0.2Ca0.1Co0.7Fe0.3O2.85 (Ln=La, Pr and Nd) Synthesized by Microwave Sintering Techniques

2013 ◽  
Vol 771 ◽  
pp. 59-62
Author(s):  
Jie Zhao ◽  
Jiang Fu ◽  
Yong Fu ◽  
Yu Na Zhao ◽  
Yong Chang Ma
Keyword(s):  
Electrical Conductivity ◽  
Cathode Materials ◽  
Small Polaron ◽  
Microwave Sintering ◽  
X Ray Diffraction ◽  
Mixed Conductivity ◽  
Polaron Hopping ◽  
Expansion Behavior ◽  
Higher Temperature

Sr, Ca and Fe doped cathode materials Ln0.7Sr0.2Ca0.1Co0.7Fe0.3O2.85 (LnSCCF, Ln=La, Pr and Nd; abbreviated as L-72173, P-72173 and N-72173) were synthesized by microwave sintering (MWS) techniques. The formation process, phase structure and composition were characterized using TG/DTA, XRD and EDS. The thermal expansion behavior of the samples was analyzed in the range of 20-950 °C by thermal dilatometer. The electrical conductivity of the samples was measured with DC four-terminal method from 25 to 900 °C. The X-ray diffraction shows that the samples exhibit a single phase with rhombohedral or cubic perovskite structure after sintered at 1200 °C for 20 min. The electrical conductivity of the samples increases with temperature up to a maximum, and then decreases gradually at higher temperature owing to the creation of oxygen vacancies. The small polaron hopping is regarded as the conducting mechanism (T 550 °C). L-72173 has higher mixed conductivity ( >300 S·cm-1) in 550-800 °C. The average TECs of L-72173, P-72173 and N-72173 are 1.389× 10-5 K-1, 1.417 × 10-5 K-1 and 1.416 × 10-5 K-1 in the range of 25-800 °C, respectively. They are thermally matched to the GDC better than the YSZ and SDC.

Coulometric Titration Studies of Nonstoichiometric Nanocrystalline Ceria

1996 ◽  
Vol 457 ◽  
Author(s):  
O. Porat ◽  
H. L. Tuller ◽  
E. B. Lavik ◽  
Y.-M. Chiang
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Vacancies ◽  
Coulometric Titration ◽  
Surface Adsorption ◽  
Oxygen Nonstoichiometry ◽  
Conductivity Data ◽  
Nanocrystalline Ceria ◽  
Electrical Conductivity Data

ABSTRACTOxygen nonstoichiometry measurements in nanocrystalline ceria, x in CeO2-x, were performed using coulometric titration. The measurements reveal large apparent deviations from stoichiometry, of the order of 10−3 − 10−4 at T = 405 − 455 °C and Po2 = 0.21 − 10−5 atm, as compared to levels of ∼10−9 for coarsened materials under the same conditions. The level of nonstoichiometry is, however, larger then expected from previous electrical conductivity data of nanocrystalline ceria. In addition, x ∝ Po2−½ while Σ ∝po2−1/6. The observed dependence of x(Po2, T) can be explained by either the formation of neutral oxygen vacancies at or near the interface, or by surface adsorption.

scholarly journals Semiconducting Thin Films of CuSbS2

Quimica Hoy ◽  
2011 ◽  
Vol 2 (1) ◽  
pp. 4
Author(s):  
Sarah Messina ◽  
Paz Hernández ◽  
Yolanda Peña
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Solid State ◽  
Optical Band Gap ◽  
Deposition Technique ◽  
X Ray ◽  
Absorber Material ◽  
Photovoltaic Applications ◽  
P Type ◽  
Semiconducting Thin Films

In this paper we present a method to produce polycrystalline CuSbS2 thin ?lms through a solid-state reaction at 350 ºC and 400 ºC involving thin ?lm multilayer of Sb2S3 -CuS or Cu2-xSe by chemical bath deposition technique. The formation of the ternary compound was confirmed by X-ray di?raction (XRD). A direct optical band gap of approx. 1.57 eV anda p-type electrical conductivity of 10-3 (Ω•cm)-1 were measured. These optoelectronic characteristics show perspective for the use of CuSbS, as a suitable absorber material in photovoltaic applications.

scholarly journals Thermoelectric Properties of Ca3Co2−xMnxO6 (x = 0.05, 0.2, 0.5, 0.75, and 1)

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 497 ◽  
Author(s):  
Nikola Kanas ◽  
Sathya Singh ◽  
Magnus Rotan ◽  
Temesgen Desissa ◽  
Tor Grande ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Self Assembly ◽  
Intermediate Phase ◽  
Small Polaron ◽  
Solid State Method ◽  
Polaron Hopping ◽  
Seebeck Coefficients ◽  
Conventional Sintering

High-temperature instability of the Ca3Co4−yO9+δ and CaMnO3−δ direct p-n junction causing the formation of Ca3Co2−xMnxO6 has motivated the investigation of the thermoelectric performance of this intermediate phase. Here, the thermoelectric properties comprising Seebeck coefficient, electrical conductivity, and thermal conductivity of Ca3Co2−xMnxO6 with x = 0.05, 0.2, 0.5, 0.75, and 1 are reported. Powders of the materials were synthesized by the solid-state method, followed by conventional sintering. The material Ca3CoMnO6 (x = 1) demonstrated a large positive Seebeck coefficient of 668 μV/K at 900 °C, but very low electrical conductivity. Materials with compositions with x < 1 had lower Seebeck coefficients and higher electrical conductivity, consistent with small polaron hopping with an activation energy for mobility of 44 ± 6 kJ/mol and where both the concentration and mobility of hole charge carriers were proportional to 1−x. The conductivity reached about 11 S·cm−1 at 900 °C for x = 0.05. The material Ca3Co1.8Mn0.2O6 (x = 0.2) yielded a maximum zT of 0.021 at 900 °C. While this value in itself is not high, the thermodynamic stability and self-assembly of Ca3Co2−xMnxO6 layers between Ca3Co4−yO9+δ and CaMnO3−δ open for new geometries and designs of oxide-based thermoelectric generators.

The Electrical Conductivity Measurements of Solid Electrolyte, CuZr2 (PO4)3

1988 ◽  
Vol 135 ◽  
Author(s):  
T.J. Lee ◽  
P.C. Yao ◽  
S.E. Hsu ◽  
D.J. Fray
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Electrical Properties ◽  
Solid Electrolyte ◽  
Copper Ion ◽  
Conductivity Measurements ◽  
Ion Conductor

AbstractThis study reports measurements of electrical properties of the solid state copper ion conductor CuZr2 (PO4)3.

Temperature Dependence of 1/f Noise and Electrical Conductivity Measurements on p-type a-Si:H Devices

2013 ◽  
Vol 1536 ◽  
pp. 181-186 ◽  
Author(s):  
V. C. Lopes ◽  
E. Hanson ◽  
D. Whitfield ◽  
K. Shrestha ◽  
C. L. Littler ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Valence Band ◽  
Hole Mobility ◽  
Type A ◽  
Localized States ◽  
Conductivity Measurements ◽  
Band Tail ◽  
Resistance Change ◽  
P Type

ABSTRACTNoise and electrical conductivity measurements were made at temperatures ranging from approximately 270°K to 320°K on devices fabricated on as grown Boron doped p-type a-Si:H films. The room temperature 1/f noise was found to be proportional to the bias voltage and inversely proportional to the square root of the device area. As a result, the 1/f noise can be described by Hooge’s empirical expression [1]. The 1/f noise was found to be independent of temperature in the range investigated even though the device conductivity changed by a factor of approximately 4 over this range. Conductivity temperature measurements exhibit a T-0.25 dependence, indicative of conduction via localized states in the valence band tail [2,3]. In addition, multiple authors have analyzed hole mobility in a-Si:H and find that the hole mobility depends on the scattering of mobile holes by localized states in the valence band tail [4-7]. We conclude that the a-Si:H carrier concentration does not change appreciably with temperature, and thus, the resistance change in this temperature range is due to the temperature dependence of the hole mobility. Our results are applicable to a basic understanding of noise and conductivity requirements for a-Si:H materials used for microbolometer ambient temperature infrared detection.

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