complex impedance analysis
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2021 ◽  
Vol 21 (11) ◽  
pp. 5707-5713
Author(s):  
M. Ramachandran ◽  
R. Subadevi ◽  
P. Rajkumar ◽  
R. Muthupradeepa ◽  
R. Yuvakkumar ◽  
...  

In the present work, pure nanocrystalline monoclinic Zirconia (ZrO2) has been successfully synthesized and optimized by the modified co-precipitation method. The concentration of raw material has been optimized with the fixed amount of precipitation agent (Potassium hydroxide KOH). The thermal history of the precursor has been examined through TG/DTA analysis. All the samples are subjected to study the structure, fingerprints of the molecular vibrations, and morphology analyses. The representative sample has been analyzed through Transmission Electron Microscope (TEM) and X-ray Photo Electron Spectroscopy (XPS) analyses. The as-prepared sample exhibits the better crystallinity and surface morphology with lesser particle size (190 nm) when the raw material concentration is 0.2 M. The as-prepared ZrO2 filler (0, 3, 6, 9, and 12 wt.%) is spread through the enhanced polymer electrolyte P(S-MMA) (27 Wt.%)-LiClO4 (8 wt.%)-EC + PC (1;1 of 65 wt.%) complex system via solution casting method. The as-synthesized electrolyte films are examined via complex impedance analysis. P(S-MMA) (27 wt.%)-LiCIO4 (8 wt.%)-EC + PC (1 ;1 of 65 wt.%)-6 wt.% of ZrO2 shows the high ionic conductivity 2.35 × 10–3 Scm–1. Temperature-dependent ionic conductivity studies obey the non-linear behavior. The enhanced ZrO2 has been expected to enhance the other electrochemical properties of the lithium secondary battery.


2021 ◽  
Vol 13 ◽  
Author(s):  
Jayanta Kumar Mishra ◽  
Khusboo Agrawal ◽  
Banarji Behera

Background: Since (1-x)[Pb(Mg1/3Nb2/3)O3]-(x)PbTiO3 (PMN-PT) ceramic has high dielectric constant and piezoelectric coefficient, it has been widely investigated for profound applications in electro-optical devices, sensors, multilayer capacitors and actuators. Objectives: The aim is to study the structural and electrical properties of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (0.7PMN-0.3PT) ceramic to understand the biphasic structural nature using Rietveld Refinement. Also, it characterises on the basis of electrical properties such as impedance and modulus to understand the relaxation process, type of conduction process as well as the role of grain and grain boundary resistance in the material. Methods: 0.7PMN-0.3PT is synthesised by mixed oxide method using PbO, MgO, Nb2O5 and TiO2 as precursor materials. Results: The XRD data reveals the biphasic structure of tetragonal phase with the space group of P4mm and monoclinic phase with the space group of Pm. The complex impedance analysis clearly represents the effect of grain on the overall resistance and departs from normal Debye type behaviour. Also, the resistance is found to decrease with temperature, thereby confirming the semiconducting nature of the sample. The presence of long as well as short-range mobility of charge carriers is confirmed from the modulus and impedance analysis. The influence of long-range motion is observed at high temperature and of short-range motion at low temperatures. Conclusion: XRD analysis confirmed the biphasic structure of M+T phase. The frequency-dependent modulus and impedance spectroscopy show the presence of a relaxation effect in the ceramic which is found to increase with temperature. The Nyquist plot shows that the resistance is decreased with temperature, thereby confirming the NTCR behaviour in the studied sample.


ACS Omega ◽  
2021 ◽  
Author(s):  
Hongmin Seo ◽  
Sunghak Park ◽  
Kang Hee Cho ◽  
Seungwoo Choi ◽  
Changwan Ko ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 927
Author(s):  
Khiat Abd Elmadjid ◽  
Felicia Gheorghiu ◽  
Mokhtar Zerdali ◽  
Ina Turcan ◽  
Saad Hamzaoui

PbTi1−xFexO3−δ (x = 0, 0.3, 0.5, and 0.7) ceramics were prepared using the classical solid-state reaction method. The investigated system presented properties that were derived from composition, microstructure, and oxygen deficiency. The phase investigations indicated that all of the samples were well crystallized, and the formation of a cubic structure with small traces of impurities was promoted, in addition to a tetragonal structure, as Fe3+ concentration increased. The scanning electron microscopy (SEM) images for PbTi1−xFexO3−δ ceramics revealed microstructures that were inhomogeneous with an intergranular porosity. The dielectric permittivity increased systematically with Fe3+ concentration, increasing up to x = 0.7. A complex impedance analysis revealed the presence of multiple semicircles in the spectra, demonstrating a local electrical inhomogeneity due the different microstructures and amounts of oxygen vacancies distributed within the sample. The increase of the substitution with Fe3+ ions onto Ti4+ sites led to the improvement of the magnetic properties due to the gradual increase in the interactions between Fe3+ ions, which were mediated by the presence of oxygen vacancies. The PbTi1−xFexO3−δ became a multifunctional system with reasonable dielectric, piezoelectric, and magnetic characteristics, making it suitable for application in magnetoelectric devices.


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