scholarly journals High Temperature Dielectric Response and AC Conductivity Mechanism of (Nd, Ni) codoped BiFeO3

2020 ◽  
Vol 1 (2) ◽  
Keyword(s):  
High Temperature ◽  
Dielectric Response ◽  
Ac Conductivity ◽  
Conductivity Mechanism

Universal ac conductivity and dielectric response of periodic chaotic systems

1993 ◽  
Vol 71 (24) ◽  
pp. 4031-4034 ◽  
Author(s):  
Nobuhiko Taniguchi ◽  
Boris L. Altshuler
Keyword(s):  
Dielectric Response ◽  
Ac Conductivity ◽  
Chaotic Systems

Dielectric response and ac conductivity analysis of hafnium oxide nanopowder

2012 ◽  
Vol 86 (6) ◽  
pp. 065703 ◽  
Author(s):  
P K Karahaliou ◽  
N Xanthopoulos ◽  
C A Krontiras ◽  
S N Georga
Keyword(s):  
Dielectric Response ◽  
Hafnium Oxide ◽  
Ac Conductivity

Electrical Performance of Cofired Alumina Substrates at High Temperatures

2013 ◽  
Vol 10 (3) ◽  
pp. 89-94 ◽  
Author(s):  
Liang-Yu Chen
Keyword(s):  
Dielectric Constant ◽  
High Temperature ◽  
Ac Conductivity ◽  
Large Scale ◽  
Dissipation Factor ◽  
Electrical Performance ◽  
Prototype System ◽  
Polycrystalline Aluminum ◽  
Polycrystalline Alumina ◽  
Dielectric Performance

A 96% polycrystalline alumina (Al2O3) based prototype packaging system with Au thick-film metallization successfully facilitated long term testing of high temperature SiC electronic devices for over 10,000 h at 500°C previously. However, the 96% Al2O3 chip-level packages of this prototype system were not fabricated via a commercial cofire process, which would be more suitable for large scale commercial production. The cofired alumina materials adopted by the packaging industry today usually contain several percent of glass constituents to allow cofiring processes at temperatures usually lower than the regular sintering temperature for alumina. In order to answer the question of whether cofired alumina substrates can provide a reasonable high temperature electrical performance comparable to regular 96% alumina sintered at 1700°C, this paper reports on the dielectric performance of a selected high temperature cofired ceramic (HTCC) alumina substrate and a low temperature cofired ceramic (LTCC) alumina (polycrystalline aluminum oxides with glass constituents) substrate from room temperature to 550°C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. Parallel-plate capacitive devices with dielectrics of these cofired alumina and precious metal electrodes were used for measurement of the dielectric properties of the cofired alumina materials in the temperature and frequency ranges. The capacitance and AC parallel conductance of these capacitive devices were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of selected LTCC and HTCC cofired alumina substrates are presented and compared with those of 96% alumina. Metallization schemes for cofired alumina for high temperature applications are discussed to address the packaging needs for low-power 500°C SiC electronics.

Electrical and Dielectric Spectroscopic Characterization of Polycrystalline Dy2Si2O7

2012 ◽  
Vol 510-511 ◽  
pp. 194-200 ◽  
Author(s):  
Shahid Ameer ◽  
Asghari Maqsood
Keyword(s):  
High Temperature ◽  
Electrical Transport ◽  
Ac Conductivity ◽  
Orthorhombic Phase ◽  
Theoretical Models ◽  
Spectroscopic Characterization ◽  
Dielectric Parameters ◽  
Triclinic Phase ◽  
Electrical Conductivities ◽  
Phase Type

The compound Dy2Si2O7exists in two polymorphs, the low temperature triclinic phase (type B) and a high temperature orthorhombic phase (type E).The dc and ac electrical conductivities of E-Dy2Si2O7are measured in the temperature range 290-510 K and frequency range 1 kHz to 1 MHz . The dc electrical transport data are analyzed according to Motts variable-range hopping model. The disorder parameter (To) and density of states at fermi level are obtained. The ac conductivity σac(ω) is obtained through the dielectric parameters. The ac conductivity can be expressed as σac(ω) =B ωs, where s is slope and it decreases with increase in temperature. The conduction mechanism in the compound is discussed in low and high temperature regions in the light of theoretical models.

Colossal dielectric response in Ba1.5Sr1.5Co2Fe24O41 ceramics at high-temperature

2018 ◽  
Vol 29 (12) ◽  
pp. 9971-9978 ◽  
Author(s):  
C. L. Li ◽  
T. Y. Yan ◽  
G. O. Barasa ◽  
Y. H. Li ◽  
R. Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Dielectric Response

Dielectric response and anhydrous proton conductivity in a chiral framework containing a non-polar molecular rotor

2015 ◽  
Vol 44 (48) ◽  
pp. 20822-20825 ◽  
Author(s):  
Shan-Shan Yu ◽  
Shao-Xian Liu ◽  
Hai-Bao Duan
Keyword(s):  
High Temperature ◽  
Proton Conductivity ◽  
Dielectric Response ◽  
Proton Conductor ◽  
Molecular Rotor ◽  
3D Framework

A chiral 3D framework containing a nonpolar rotor shows two dielectric anomalies and can serve as a proton conductor under high-temperature and anhydrous conditions.

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