Polaronic conduction in lanthanum strontium chromite

1977 ◽  
Vol 55 (19) ◽  
pp. 1725-1731 ◽  
Author(s):  
J. B. Webb ◽  
M. Sayer ◽  
A. Mansingh
Keyword(s):  
Transport Properties ◽  
Room Temperature ◽  
Ceramic Materials ◽  
Localized States ◽  
Defect Band ◽  
Barrier Effects ◽  
Lanthanum Strontium ◽  
Dc And Ac Conductivity ◽  
Polycrystalline Ceramic ◽  
Polaron Radius

In many polycrystalline ceramic materials the transport properties are strongly affected by internal barrier effects or by the presence of contact barriers. The transport properties of La1−xSrxCrO3, 0 ≤ x ≤ 0.2 have been investigated and the degree to which these barriers affect the measured transport properties has been established. Measurements of the dc and ac conductivity in the range 77 K ≤ T ≤ 1300 K are consistent with the hopping of polarons in a defect band of localized states at the Fermi energy with the thermopower essentially independent of temperature. A polaron radius of 3.5 Å has been determined with room temperature mobility of 5 × 10−4 cm2 V−1 s−1.

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

2021 ◽  
Author(s):  
Haohao Sheng ◽  
Haoxiang Long ◽  
Guanzhen Zou ◽  
Dongmei Bai ◽  
Junting Zhang ◽  
...  
Keyword(s):  
Transport Properties ◽  
Room Temperature ◽  
Phonon Transport ◽  
Two Dimensional

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

Interpreting equilibrium-conductivity and conductivity-relaxation measurements to establish thermodynamic and transport properties for multiple charged defect conducting ceramics

2015 ◽  
Vol 182 ◽  
pp. 49-74 ◽  
Author(s):  
Huayang Zhu ◽  
Sandrine Ricote ◽  
W. Grover Coors ◽  
Robert J. Kee
Keyword(s):  
Transport Properties ◽  
Material Properties ◽  
Ceramic Materials ◽  
Barium Zirconate ◽  
Charged Defect ◽  
Conductivity Measurements ◽  
Conductivity Relaxation ◽  
Kinetics Parameters ◽  
Relaxation Measurements ◽  
Thermodynamic And Transport Properties

A model-based interpretation of measured equilibrium conductivity and conductivity relaxation is developed to establish thermodynamic, transport, and kinetics parameters for multiple charged defect conducting (MCDC) ceramic materials. The present study focuses on 10% yttrium-doped barium zirconate (BZY10). In principle, using the Nernst–Einstein relationship, equilibrium conductivity measurements are sufficient to establish thermodynamic and transport properties. However, in practice it is difficult to establish unique sets of properties using equilibrium conductivity alone. Combining equilibrium and conductivity-relaxation measurements serves to significantly improve the quantitative fidelity of the derived material properties. The models are developed using a Nernst–Planck–Poisson (NPP) formulation, which enables the quantitative representation of conductivity relaxations caused by very large changes in oxygen partial pressure.

Effect of sintering temperature on the transport properties of La2Ce2O7 ceramic materials

2021 ◽  
Author(s):  
Bishnu Choudhary ◽  
Sharmistha Anwar ◽  
Medvedev Dmitry Andreevich ◽  
Laxmidhar Besra ◽  
Shahid Anwar
Keyword(s):  
Transport Properties ◽  
Sintering Temperature ◽  
Ceramic Materials

scholarly journals Effect of LiNbO3 on the Electrocaloric Performance of 0.94BNT-0.06BT Ceramic Materials

2021 ◽  
Author(s):  
Jing Chen ◽  
lei Wu ◽  
Luanfan Duan ◽  
Dongren Liu
Keyword(s):  
Ceramic Material ◽  
Room Temperature ◽  
Ceramic Materials ◽  
Adiabatic Temperature ◽  
Cooling Effect ◽  
Material System ◽  
Temperature Changes ◽  
Cooling Temperature ◽  
Temperature Range

Abstract Considering that the electric refrigeration temperature range of 0.94BNT-0.06BT ceramic materials is 100 ~ 140℃, the electric refrigeration performance of the 0.94BNT-0.06BT ceramic material system was modified by LiNbO3 doping to reduce the cooling temperature. As a result, the refrigeration temperature range of the 0.94BNT-0.06BT ceramic material system was lowered to 25 ~ 80℃, achieving its cooling effect near room temperature, and in this temperature range, the adiabatic temperature changes ∆T > 0.6K.

scholarly journals Low-temperature transport properties of n-type layered homologous compounds Bi8−xSbxSe7

2020 ◽  
Vol 8 (40) ◽  
pp. 14037-14048
Author(s):  
Pavan Kumar-Ventrapati ◽  
Shantanu Misra ◽  
Gaëlle Delaizir ◽  
Anne Dauscher ◽  
Bertrand Lenoir ◽  
...  
Keyword(s):  
Low Temperature ◽  
Transport Properties ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Parent Compound ◽  
New Class ◽  
Highly Efficient ◽  
Homologous Compounds

The n-type chalcogenide Bi8Se7 is the parent compound of a new class of highly-efficient thermoelectric materials for near-room-temperature thermoelectric applications.

Detection of cracks in scratching tests in ceramic materials through acoustic emission

2005 ◽  
Vol 219 (9) ◽  
pp. 685-693 ◽  
Author(s):  
L E A Sanchez ◽  
J F G Oliveira ◽  
R T Coelho
Keyword(s):  
Acoustic Emission ◽  
Material Removal ◽  
Gradual Increase ◽  
Ceramic Materials ◽  
Polycrystalline Alumina ◽  
Testing Conditions ◽  
Emission Signal ◽  
Diamond Indenter ◽  
Different Types ◽  
Polycrystalline Ceramic

The mechanisms of material removal and the interactions among scratches performed in ceramic materials were investigated using acoustic emission signals, and scanning electron microscopy, in scratching experiments. Several testing conditions were used to produce different types of removing mechanism on a glass as well as on a polycrystalline alumina sample composed by heterogeneous grain size. It is known that the material removing process on a polycrystalline ceramic involves intergranular microfracture and grain dislodgement, unlike the chipping produced by the extension of lateral cracks in non-granular materials, such as glass. Distinct settings for velocities, loads, and two types of diamond indenter were tested. The material removal was carried out by three different methods of scratching: single passes, repeated overlapping passes, and parallel scratches. As a general result, there was a clear relationship between the acoustic emission signals and the damage intensity occurred in the material removal. More specifically there were differences in the acoustic emission signal levels in the scratches made on the alumina and on the glass owing to the material removal mechanisms associated with the structure of these materials. A gradual increase in the acoustic emission levels was observed when the number of repeated passes was increased as a result of the damage accumulation process followed by severe material removal. It was also noticed that the acoustic emission signals were capable of reflecting the interactions between two parallel scratches.

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