Low- Frequency Dielectric Dispersion and Impedance Spectroscopy of Lead-Free Na0.5 Bi0.5 Tio3 (NBT) based Ferroelectric Ceramic

A new lead-free ferroelectric relaxor ceramic was prepared by conventional solid-state synthesis by modifying A-site and B-site in (Na0.5Bi0.5)TiO3 system, i.e., (Na0.5Bi0.5)0.95Ba0.05Zr0.04Ti0.96O3 (0.05BNBZT). X-ray diffraction studies reveal a single phase rhombohedral structure. Crystallite size and strain analysis has been done by Debye–Scherrer and Williamson–Hall technique. The tolerance factor is 0.81, indicating a stable Perovskite structure of the material. Scanning electron micrograph of the material shows a distribution of grains, average grain size is 1.41 μm. Dielectric response of (Na0.5Bi0.5)0.95Ba0.05 Zr0.04Ti0.96O3 , ferroelectric ceramic has been studied as a function of frequency over a wide range of temperatures. The studied ceramic exhibited maximum frequency dispersion in both real and imaginary part of dielectric susceptibility at and around the dielectric transition temperature (Tm). The frequency dependence of transition temperature, Tm (temperature of the maximum of dielectric constant) was studied in terms of Vogel–Fulcher relation. The dielectric relaxation of (Na0.5Bi0.5)0.95Ba0.05Zr0.04Ti0.96O3 ceramic was studied at different temperatures using the complex impedance (Z*) and electrical modulus (M*) formalism. Impedance measurements were made on over a wide range of temperatures (300–600°C) and frequencies (45 Hz–5 MHz) which show the presence of both grain and grain boundary effects in the material. The Impedance spectroscopy is shown to be an efficient method capable of detecting the contributions of the resistances of grain boundaries (at higher temperature), in addition to granular contribution (at all temperatures), which influences the device properties of a material. The electric modulus (M*) formalism used in the analysis enabled us to distinguish and separate the relaxation processes. Conductivity studies in the material obey the Jonscher's power law in frequency (45 Hz–5 MHz) and temperature (30–600°C). These results give evidence that the lead-free ferroelectric ceramics is extensively may be used for device and electronic applications, when compared with lead-based materials.

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Electrocaloric properties of lead-free ferroelectric ceramic near room temperature

Applied Physics A ◽

10.1007/s00339-021-04604-8 ◽

2021 ◽

Vol 127 (6) ◽

Author(s):

Hend Kacem ◽

Ah. Dhahri ◽

Mohamed Amara Gdaiem ◽

Z. Sassi ◽

L. Seveyrat ◽

...

Keyword(s):

Room Temperature ◽

Ferroelectric Ceramic ◽

Lead Free

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Study of Influence of Electrode Geometry on Impedance Spectroscopy

ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 2 ◽

10.1115/fuelcell2010-33209 ◽

2010 ◽

Cited By ~ 3

Author(s):

Riaz Ahmed ◽

Kenneth Reifsnider

Keyword(s):

Impedance Spectroscopy ◽

High Frequency ◽

Low Frequency ◽

Effective Area ◽

Ac Impedance ◽

Local Geometry ◽

Electrode Geometry ◽

Electrode Area ◽

Impedance Response ◽

Working Electrode

Electrochemical Impedance Spectroscopy (EIS) is a powerful and proven tool for analyzing AC impedance response. A conventional three electrode EIS method was used to perform the investigation in the present study. Saturated potassium chloride solution was used as the electrolyte and three different material rods were used as working electrodes. Different configurations of electrode area were exposed to the electrolyte as an active area to investigate electrode geometry effects. Counter to working electrode distance was also altered while keeping the working electrode effective area constant to explore the AC response dependence on the variation of ion travel distance. Some controlled experiments were done to validate the experimental setup and to provide a control condition for comparison with experimental results. A frequency range of 100 mHz to 1 MHz was used for all experiments. In our analysis, we have found a noteworthy influence of electrode geometry on AC impedance response. For all electrodes, impedance decreases with the increase of effective area of the electrolyte. High frequency impedance is not as dependent on geometry as low frequency response. The observed phase shift angle drops in the high frequency region with increased working electrode area, whereas at low frequency the reverse is true. Resistance and capacitive reactance both decrease with an increase of area, but resistance response is more pronounce than reactance. For lower frequencies, small changes in working area produce very distinctive EIS variations. Electrode material as well as geometry was systematically varied in the present study. From these and other studies, we hope to develop a fundamental foundation for understanding specific changes in local geometry in fuel cell (and other) electrodes as a method of designing local morphology for specific performance.

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Low-frequency dielectric dispersion in NaNbO3single crystals

Ferroelectrics ◽

10.1080/00150199808229550 ◽

1998 ◽

Vol 215 (1) ◽

pp. 65-73 ◽

Cited By ~ 8

Author(s):

K. Konieczny ◽

Cz. Kajtoch

Keyword(s):

Low Frequency ◽

Dielectric Dispersion

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Low-frequency dielectric dispersion in Ni3B7O13I

Czechoslovak Journal of Physics ◽

10.1007/bf01587124 ◽

1974 ◽

Vol 24 (2) ◽

pp. 231-234 ◽

Cited By ~ 8

Author(s):

F. Smutný ◽

J. Fousek ◽

M. Kotrbová

Keyword(s):

Low Frequency ◽

Dielectric Dispersion

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Dielectric Behavior of Mechano-chemically Synthesized [(CH3NH3)3Bi2Br9]: A Lead Free Hybrid Perovskite

10.21203/rs.3.rs-218681/v1 ◽

2021 ◽

Author(s):

Swagatalaxmi Pujaru ◽

Priyabrata Sadhukhan ◽

Basudev Ghosh ◽

Arup Dhara ◽

Sachindranath Das

Keyword(s):

Impedance Spectroscopy ◽

Complex Impedance ◽

Negative Temperature ◽

Dielectric Behavior ◽

Lead Free ◽

Published Data ◽

Temperature Dependent ◽

Microstructural Parameters ◽

Hybrid Perovskite ◽

Refinement Method

Abstract Lead free hybrid halide perovskite (CH3NH3)3Bi2Br9 has been successfully synthesized by mechano-chemical method. The microstructure analysis by Rietveld’s refinement method revealed that the crystal belongs to trigonal system with space group P3 ̅m1. The obtained microstructural parameters are well in agreement with the previously published data. Temperature-dependent ac conductivity, impedance spectroscopy, and complex dielectric properties have been investigated in detail. The negative temperature coefficient of resistance behaviour reveals the semiconducting nature of the materials. The complex impedance spectroscopy also supports the semiconducting nature of the sample with activation energy for conduction ~0.38 eV.

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