Colossal dielectric permittivity in Co-doped ZnO ceramics prepared by a pressure-less sintering method

2018 ◽  
Vol 20 (45) ◽  
pp. 28712-28719 ◽  
Author(s):  
H. V. S. Pessoni ◽  
P. Banerjee ◽  
A. Franco
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Spectroscopic Studies ◽  
Reaction Method ◽  
Doped Zno ◽  
Sintering Method ◽  
Zno Ceramics ◽  
Co Doped

Dielectric properties and impedance spectroscopic studies of single phase Zn1−xCoxO (0 ≤ x ≤ 0.05) ceramics, synthesized by a pressure-less solid state reaction method, have been carried out to investigate the origin of colossal dielectric permittivity (CP), ε′ ∼ 105, in a wide frequency (2 × 101–2 × 106 Hz) range.

Microwave Dielectric Properties of (1-x)(Ca0.61Nd0.26)TiO3–x(Li0.5Sm0.5)TiO3

2007 ◽  
Vol 336-338 ◽  
pp. 287-289
Author(s):  
Wei Wang ◽  
Zi Long Tang ◽  
Zhong Tai Zhang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Temperature Coefficients ◽  
Microwave Dielectric ◽  
Optimum Parameters ◽  
Xrd Patterns

(1-x)(Ca0.61Nd0.26)TiO3-x(Li0.5Sm0.5)TiO3 (0.2 ≤ x ≤ 0.7) ceramics were prepared by solid-state reaction method and the microwave dielectric properties of the resultant materials at different (Li0.5Sm0.5)TiO3 contents were investigated. A single phase of perovskite in all samples was confirmed by XRD patterns. With increasing (Li0.5Sm0.5)TiO3 content, Q×f value and dielectric constant (εr) decrease slightly and the temperature coefficients of the resonant frequency (τf) of the specimens decreases noticeably. The optimum parameters, i.e.,εr = 109, Q×f = 5259 GHz and τf = ~0 ppm/°C, for the composition of 0.4(Ca0.61Nd0.26)TiO3-0.6(Li0.5Sm0.5)TiO3 was obtained when keep the calcination temperature at 1250°C for 3 h.

INFLUENCE OF SAMARIUM SUBSTITUTION ON DIELECTRIC PROPERTIES OF BARIUM TITANATE BASED CERAMICS

2009 ◽  
Vol 23 (28) ◽  
pp. 3419-3425 ◽  
Author(s):  
PARVEEN KUMAR ◽  
SANGEETA SINGH ◽  
J. K. JUNEJA ◽  
CHANDRA PRAKASH ◽  
K. K. RAINA
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Barium Titanate ◽  
Curie Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Dielectric Behavior ◽  
Reaction Method ◽  
X Ray ◽  
Material Series

In this paper we report samarium substituted Ba 0.80 Pb 0.20 Ti 0.90 Zr 0.10 O 3 (BPZT) ceramics. The material series with compositional formula Ba 0.80-x Sm x Pb 0.20 Ti 0.90 Zr 0.10 O 3 with x varying from 0 to 0.01 in the steps of 0.0025 was chosen for investigations. The material was synthesized by solid state reaction method. Reacted powders compacted in the form of circular discs were sintered at 1325°C. All the samples were subjected to X-ray analysis and found to be single phase. Dielectric behavior was studied as a function of frequency and temperature and Curie temperature (Tc) was determined. Tc was found to decrease with increasing x. The details are discussed and presented here.

Effect of Li2CO3-V2O5 on the Sintering and Microwave Dielectric Properties of 0.6Mg4Nb2O9-0.4SrTiO3 Composite Ceramics

2010 ◽  
Vol 663-665 ◽  
pp. 608-611
Author(s):  
Cui Jin Pei ◽  
Guo Guang Yao ◽  
Xiu Lao Tian ◽  
Hong Ma
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Composite Ceramics ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Microwave Dielectric ◽  
Co Doped

The effects of Li2CO3-V2O5 (LV) co-doped on the sinterability, phase compositions and microwave dielectric properties of 0.6Mg4Nb2O9-0.4SrTiO3 composite ceramics have been investigated. All specimens were prepared by solid-state reaction method and sintered at 1050-1200oC for 5h. With an amount LV addition, the densification sintering temperature is significantly lowed from 1300oC to 1175oC. The non-stoichiometric compounds Sr(NbTi)O3+δ and Mg4(Nb1-xTix)2O9-δ were confirmed by X-ray diffraction and energy dispersive X-ray analysis. For the specimen with 1.5 wt% LV addition sintered at 1175oC for 5 h exhibited dielectric properties: εr=20.1, Q•f=10 240 GHz, τf =0.15 ppm/oC.

scholarly journals An experimental and theoretical insights into the dielectric properties of (Li, Nd) co-doped ZnO ceramics

2020 ◽  
Vol 31 (22) ◽  
pp. 20113-20128
Author(s):  
Md. Zahidur Rahaman ◽  
Hidekazu Tanaka ◽  
A. K. M. Akther Hossain
Keyword(s):  
Dielectric Properties ◽  
Doped Zno ◽  
Zno Ceramics ◽  
Co Doped

Electron-pinned defect dipoles in (Li, Al) co-doped ZnO ceramics with colossal dielectric permittivity

2020 ◽  
Vol 8 (9) ◽  
pp. 4764-4774 ◽  
Author(s):  
Dong Huang ◽  
Wen-Long Li ◽  
Zhi-Fu Liu ◽  
Yong-Xiang Li ◽  
Cuong Ton-That ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Co Doping ◽  
Low Dielectric ◽  
Doped Zno ◽  
Colossal Dielectric Constant ◽  
Zno Ceramics ◽  
Co Doped

The colossal dielectric constant and relatively low dielectric loss (εr = 9862 and tan δ = 0.159) in ZnO ceramics have been achieved via acceptor and donor co-doping method.

Microstructure and Thermoelectric Properties of Na0.5CoO2

2013 ◽  
Vol 802 ◽  
pp. 218-222 ◽  
Author(s):  
Wanatchaporn Namhongsa ◽  
Tosawat Seetawan ◽  
Pennapa Muthitamongkol ◽  
Chanchana Thanachayanont
Keyword(s):  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Powder Size ◽  
Sodium Ions ◽  
Small Particle Size ◽  
Orthorhombic Structure ◽  
Sodium Cobalt Oxide ◽  
Sintering Method

The polycrystalline of sodium cobalt oxide (Na0.5CoO2) was synthesized by solid state reaction method and sintering method. The microstructure was composed of powder size and crystal structure. The Seebeck coefficient and electrical resistivity are measured. We found that the concentration of sodium ions sandwiched between two neighboring CoO2layers played a crucial role in transport properties. The results showed small particle size, single phase and orthorhombic structure. The Seebeck coefficient of Na0.5CoO2increased as the temperature increased. The electrical resistivity was decreased as temperature decreased from the range 300-500 K.

Study on ferroelectric and dielectric properties of Li-doped ZnO ceramics and thin films prepared by PLD method

2001 ◽  
Vol 252 (1) ◽  
pp. 265-271 ◽  
Author(s):  
Z. C. Wu ◽  
X. M. Zhang ◽  
J.-M. Liu ◽  
Q. C. Li ◽  
X. Y. Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Doped Zno ◽  
Zno Ceramics

scholarly journals Structure and electric properties of cerium substituted SrBi1.8Ce0.2Nb2O9 and SrBi1.8Ce0.2Ta2O9 ceramics

2016 ◽  
Vol 10 (3) ◽  
pp. 183-188 ◽  
Author(s):  
Mohamed Afqir ◽  
Amina Tachafine ◽  
Didier Fasquelle ◽  
Mohamed Elaatmani ◽  
Jean-Claude Carru ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Room Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Lcr Meter ◽  
Curie Temperature Tc

SrBi1.8Ce0.2Nb2O9 (SBCN) and SrBi1.8Ce0.2Ta2O9 (SBCT) powders were prepared via solid-state reaction method. X-ray diffraction analysis reveals that the SBCN and SBCT powders have the single phase orthorhom-bic Aurivillius structure at room temperature. The contribution of Raman scattering and FTIR spectroscopy of these samples were relatively smooth and resemble each other. The calcined powders were uniaxially pressed and sintered at 1250?C for 8 h to obtaine dense ceramics. Dielectric constant, loss tangent and AC conductivity of the sintered Ce-doped SrBi2Nb2O9 and SrBi2Ta2O9 ceramics were measured by LCR meter. The Ce-doped SBN (SBCN) ceramics have a higher Curie temperature (TC) and dielectric constant at TC (380?C and ?? ~3510) compared to the Ce-doped SBT (SBCT) ceramics (330?C and ?? ~115) when measured at 100Hz. However, the Ce-doped SBT (SBCT) ceramics have lower conductivity and dielectric loss.

Investigation on structural, optical and dielectric properties of Co doped ZnO nanoparticles synthesized by gel-combustion route

2012 ◽  
Vol 177 (5) ◽  
pp. 428-435 ◽  
Author(s):  
Sajid Ali Ansari ◽  
Ambreen Nisar ◽  
Bushara Fatma ◽  
Wasi Khan ◽  
A.H. Naqvi
Keyword(s):  
Dielectric Properties ◽  
Zno Nanoparticles ◽  
Gel Combustion ◽  
Combustion Route ◽  
Doped Zno ◽  
Co Doped

Synthetic Processes via Complex Precursors of Rare Earth Manganites with the Perovskite and its Related Structures

2004 ◽  
Vol 449-452 ◽  
pp. 725-728 ◽  
Author(s):  
A. Shimono ◽  
Hirohisa Sato ◽  
K. Kawada-Wada ◽  
Yasuo Ito ◽  
Naoki Kamegashira
Keyword(s):  
Rare Earth ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Rare Earth Complex ◽  
Normal Process ◽  
Composition Region ◽  
Synthetic Process ◽  
Reaction Method ◽  
X Ray ◽  
Rare Earth Manganites

A development of synthetic process via rare earth complex precursors was applied to a formation of rare earth manganites which can not be easily formed by conventional (normal) process. Several compounds of rare earth manganites with various structures were successfully synthesized by this method and their crystal structures were identified by powder X-ray diffractometry. Both of the orthorhombic and rhombohedral LaMnO3phases were prepared. LnMn2O5phase was more easily prepared by this method than by another method. The solid solution of (Sr,La)2MnO4phase for various compositions were tried to prepare a single phase, especially for a composition region Sr/La ratio < 1. since this phase is normally formed for only region of Sr/La ratio .. 1 by the solid state reaction method.

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