ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Peer Reviewed and Refereed Journal (International Journal) ISSN-2456-1037
Vol. 05,Special Issue 01, (ICOSD-2020) January 2020, Available Online:
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STUDY OF PEROVSKITE- RELATED OXIDES HAVING HIGH DIELECTRIC CONDUCTIVITY OF 0.83Ba (Fe0.5Nb0.5) O3-0.17BaTiO3 [BFN+BT] CERAMICS
1Pritam Kumar, 2Sarita Chourasia and 3N. K. Singh
1Lakshmi Narain College of Technology and Science, (R.I.T.), Indore, (M. P.)
2University Department of Physics, V. K. S. University, Ara 802301 Bihar, India
Abstract- Complex perovskite material 0.83Ba (Fe0.5Nb0.5) O3-0.17BaTiO3 (BT-BFN) is synthesized by a solid state-reaction technique. The dielectric conductivity of the sample is measured in the temperature range of 30°C-400°C and in the frequency range of 100Hz-1MHz. Ac conductivity measurements have been widely used to investigate the nature of ionic motion in ionically conducting materials such as BT-BFN ceramics. The presence of both the high and low frequency plateaus in conductivity spectra suggests that the two processes are contributing to the bulk conduction behavior. Studies of structural characterizations were performed by X-ray diffraction (XRD) techniques. X-ray studies reveal that the BT-BFN has monoclinic structure at room temperature. We will discuss in details of this research review paper in the said international conference.
Keywords: X-ray diffraction; SEM; Perovskite Structure.
1. INTRODUCTION
Electrical conductivity is an important experiment tool to probe the structural defects and internal purity of semi-insulating crystalline solids, because unlike metals and semiconductors where electrons are the charge carriers, in semi-insulators the prime factors contributing to their electrical conductivity are the crystal defects [1]. For the development of capacitors, many investigators have tried to synthesize and study the materials that exhibit dielectric constant [1-5].
When the dielectric is placed in alternating fields, these polarizations are set up giving rise to the dielectric constant. A temporal phase shift is found to occur between the driving field and the resulting polarization and the loss current component appears giving rise to the dielectric loss (tanδ). The relative dielectric constant, ε/ε0 is the relation between the charge stored on an electrode slab of materials brought to a given voltage and charge stored on a set of identical electrodes separated by vacuum. It is dimensionless. There are several types of polarizations, each of which can be explained by its intrinsic physical mechanism.
2. EXPERIMENTAL DETAILS
From the measurement, we have obtained capacitance (C) and tangent loss (tanδ) of the samples as a function of frequency (100 Hz to 1 MHz) at different temperature (30°C–400°C) using a PSM (Comm.1735). The X-ray powder diffraction pattern of the sample is taken at room temperature using a X-ray powder diffractometer (Rigaku Miniflex, Japan) using Cukα
radiation (λ = 1.5418 Å) in a wide range of Bragg angles 2θ (20° ≤ 2θ ≤ 80°) with scanning rate 2°/min. The micrographs are recorded using scanning electron microscopy JEOL-JSM-5800 to study the surface morphology/microstructure of the sintered pellets.
3. RESULTS & DISCUSSIONS
The sharp and single reflection peaks of the XRD pattern shows the formation of single-phase with monoclinic structure of BT-BFN ceramics is shown in Fig. 1. The lattice parameters of the selected unit cell were refined using the least-squares subroutine of a standard computer program package “POWD” [5]. Our results are in agreement with those by Intatha et al. [6], Fang et al. [7], Nedelcu et al.[8], Yokosuka [9], Tezuka et al. [10], Raevski et al. [11], and Saha and Sinha [12, 13] who also prepared this compound by solid-state reaction.
ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Peer Reviewed and Refereed Journal (International Journal) ISSN-2456-1037
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Fig. 1 XRD of BT-BFN ceramics at room temperature
The relationship between the ac conductivity and the applied frequency at different constant temperature values is shown in Fig.2. The conductivity shows dispersion which shifts to higher frequency side with the increase of temperature. One may distinguish two types of plateau: one at low frequency plateau (DC conductivity) and high frequency plateau.
Fig. 2 frequency dependence of Ac conductivity of the sample at different constant temperature values.
A broader plateau region is observed in the low frequency region and a dispersive behavior of conductivity spectrum appears in the high frequency region irrespective of temperature.
4. CONCLUSIONS
BaTiO3 doped Ba(Fe0.5Nb0.5)O3 ie. 0.83Ba (Fe0.5Nb0.5) O3-0.17BaTiO3 (BT-BFN) were synthesized by the tradition solid-state reaction method. The XRD patterns of the BFN and BT-BFN at room temperature show a monoclinic phase. The field dependence of conductivity of the sample is measured in the temperature range of 30°C-400°C and in the frequency range of 100Hz - 5MHz.
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ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Peer Reviewed and Refereed Journal (International Journal) ISSN-2456-1037
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