Evidence of large hopping polaron conduction process in strontium doped calcium copper titanate ceramics

2019 ◽  
Vol 556 ◽  
pp. 36-41 ◽  
Author(s):  
S. Amhil ◽  
E. choukri ◽  
S. Ben Moumen ◽  
A. Bourial ◽  
L. Essaleh
Keyword(s):  
Conduction Process ◽  
Calcium Copper Titanate ◽  
Polaron Conduction ◽  
Titanate Ceramics

Microstructure and Electrical Properties of Calcium Copper Titanate Ceramics

2007 ◽  
Vol 561-565 ◽  
pp. 551-555 ◽  
Author(s):  
Lai Jun Liu ◽  
Hui Qing Fan
Keyword(s):  
Electrical Properties ◽  
Dielectric Permittivity ◽  
High Frequency ◽  
Low Frequency ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Cell Parameters ◽  
Grain Sizes ◽  
Calcium Copper Titanate ◽  
Titanate Ceramics

The effect of stoichiometry, i.e. Ca/Cu ratios (CaCu3xTi4O12, x = 0.8, 0.9, 1.0, 1.1 and 1.2) on the microstructure and electrical properties was investigated. The grain sizes of CaCu3xTi4O12 composition increased sharply with the increase of copper, from ~1 μm with x = 0.8 to ~50 μm with x = 1.2. The real part of dielectric permittivity changed dramatically, the pellet with x = 1.0 had the highest dielectric permittivity ~160, 000 at 1 kHz. Furthermore, the dielectric permittivity of all pellets was impressively large values (between 10, 000 to 1, 000,000 at 100 Hz) and was nearly constant over a wide frequency range between 100 Hz to ~100 MHz. However, the dielectric permittivity of CaCu3xTi4O12 composition is not consistent with the amount of copper and cell parameters and grain sizes. Impedance spectroscopy exhibited that the CaCu3xTi4O12 composition had two semicircle at least at high frequency (~ 107 Hz) and low frequency (<100 Hz), respectively. The grain and grain boundary of the compositions had different impedance and relaxation behavior.

Influence of atmospheres on the dielectric properties of calcium copper titanate ceramics

2019 ◽  
Vol 102 (9) ◽  
pp. 5271-5283
Author(s):  
Disna P. Samarakoon ◽  
Nirmal Govindaraju ◽  
Raj N. Singh
Keyword(s):  
Dielectric Properties ◽  
Calcium Copper Titanate ◽  
Titanate Ceramics

Dielectric Properties of Sol-Gel Prepared Ni-Doped CaCu3Ti4O12 Ceramics

2012 ◽  
Vol 204-208 ◽  
pp. 4193-4196
Author(s):  
Lei Jiao ◽  
Hui Li ◽  
Yan Wei Yang ◽  
Tian Ping Wang
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Low Frequency ◽  
Frequency Region ◽  
Dielectric Constants ◽  
High Frequency Region ◽  
Xrd Pattern ◽  
Calcium Copper Titanate ◽  
Titanate Ceramics

Dielectric properties of sol–gel prepared Ni-doped calcium copper titanate Ceramics (CCNTO) are investigated. For the x of CaCu3NixTi4O12+x is 0, 0.1, 0.2, 0.3 respectively. The XRD pattern shows that crystal structure of the sample without Ni is basically single-phase. The dielectric properties of CCNTO were analyzed by Agilent 4294A. The experimental results show that the sample has a better dielectric properties when x=0.2. The maximum dielectric constants is found when x=0.2. The dielectric loss decreased with the increases of Ni in the low frequency region, the high frequency region is just the opposite, the sample has lower dielectric loss in the low frequency region when x=0.2.

Influence of Alumina Dopant and Environment on the Electrical Properties of Calcium Copper Titanate Ceramics

2021 ◽  
Vol 21 (4) ◽  
pp. 2148-2162
Author(s):  
Disna P. Samarakoon ◽  
Raj N. Singh
Keyword(s):  
Dielectric Properties ◽  
Nitrogen Atmosphere ◽  
Charge Accumulation ◽  
Low Frequencies ◽  
Testing Environment ◽  
Calcium Copper Titanate ◽  
Large Dielectric Constant ◽  
Electrical And Dielectric Properties ◽  
The Stability ◽  
Titanate Ceramics

Calcium copper titanate (CaCu3Ti4O12; CCTO) ceramics are useful as capacitor dielectrics for many applications. In this study the effect of doping with alumina and testing atmospheres in air and dry N2 on the stability and reproducibility of electrical and dielectric properties of CCTO-xAl2O3 system, where x = 0, 0.5, and 4 wt.% as a function of temperature are investigated. Solid-state synthesis route is used to fabricate the pure and doped CCTO samples sintered at 1080 °C and 1100 °C for 5 h in air. Stable and reproducible dielectric properties are obtained only by switching the measuring atmosphere from air to dry N2. Increased space charge accumulation at the grain boundaries leading to large dielectric constant (ε′) and tan δ are measured in air. Much lower tan δ values of 0.021–0.020 are obtained with a large ε′ (8,815–11,090) at low frequencies (500–800 Hz) in N2 at 23 °C for 0.5 wt.% alumina in both samples sintered at 1080 °C and 1100 °C. These results clearly demonstrate that testing environment can dominate the dielectric properties of pure and alumina-doped CCTO at low frequencies unless measured in dry nitrogen atmosphere to achieve intrinsic behavior useful for applications as capacitors.

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