Investigation of AC electrical conductivity and dielectric properties of BiBaFeZnO6 double perovskite oxides

2021 ◽  
Vol 32 (19) ◽  
pp. 24050-24057
Author(s):  
K. Iben Nassar ◽  
M. Slimi ◽  
N. Rammeh ◽  
A. Bouhamed ◽  
A. Njeh ◽  
...  
2018 ◽  
Vol 63 (8) ◽  
pp. 754 ◽  
Author(s):  
A. Hashim ◽  
A. Hadi

This paper aims to the preparation of novel pressure-sensitive nanocomposites with low cost, light weight, and good sensitivity. The nanocomposites of polyvinyl alcohol, polyacrylic acid, and lead oxide nanoparticles have been investigated. The dielectric properties and dc electrical conductivity of (PVA–PAA–PbO2) nanocomposites have been studied. The dielectric properties of nanocomposites were measured in the frequency range (100 Hz–5 MHz). The experimental results showed that the dielectric constant and dielectric loss of (PVA–PAA–PbO2) nanocomposites decrease, as the frequency increases, and they increase with the concentrations of PbO2 nanoparticles. The ac electrical conductivity of (PVA–PAA–PbO2) nanocomposites increases with the frequency and the concentrations of PbO2 nanoparticles. The dc electrical conductivity of (PVA–PAA–PbO2) nanocomposites also increases with the concentrations of PbO2 nanoparticles. The application of pressure-sensitive nanocomposites has been examined in the pressure interval (60–200) bar. The results showed that the electrical resistance of (PVA–PAA–PbO2) pressure-sensitive nanocomposites decreases, as the compressive stress increases. The (PVA–PAA–PbO2) nanocomposites have high sensitivity to pressure.


2019 ◽  
Vol 6 (9) ◽  
pp. 096306
Author(s):  
Ekramul Kabir ◽  
M Khatun ◽  
Raihan J Mustafa ◽  
Kiran Singh ◽  
Muklesur Rahman

2013 ◽  
Vol 28 (01) ◽  
pp. 1350200
Author(s):  
SHRIPAL SHARMA ◽  
RAKESH SINGH ◽  
GEETIKA

Manganese doped derivatives of polycrystalline Na 1.89 Li 0.10 K 0.01 Ti 3 O 7 bearing 0.01, 0.05 and 1.0 molar % of manganese have been prepared by chemical synthesis. The results of ac electrical conductivity studies in form of log (σT) versus 1000/T plots are reported in the frequency and temperature range of 10 kHz–1 MHz and 350–775 K, respectively. The corresponding plots have been divided into five temperature regions, I, II, III, IV and V. The various conduction mechanisms in different regions have been discussed. The nature of conductivity has been explained by proposing a model about the obtained conductivity σ(ω) which is the sum of three terms arising from three different mechanisms. Moreover, various Na–K–Li–O–Ti–O linkages in Na 2-x-y Li x K y Ti 3 O 7 materials may result special forms of electron clouds. Experimental results of the loss tangent ( tan δ) and relative permittivity (εr) versus temperature at different frequencies have been described. The results of tan δ and εr versus frequency plots at different temperature have also been given for these doped derivatives.


2020 ◽  
Author(s):  
seyed ebrahim Mousavi Ghahfarokhi ◽  
Foruzan Bazdar ◽  
Iraj Kazeminezhad ◽  
Elham Mohammadzadeh Shobegar

Abstract PbFe12-xNixO19 nanoparticles (x = 0-1) were prepared by a sol–gel method. The influence of Ni2+ substitution on structural, magnetic and dielectric properties of PbFe12O19 nanoparticles was investigated. The samples of PbFe12-xNixO19 nanoparticles have been characterized by the X-ray diffractomere (XRD), Fourier transform infrared spectrometer (FT-IR), scanning electron spectrometer (SEM), vibrating sample magnetometer (VSM), and an LCR meter. The results reveal that PbFe12-xNixO19 compounds up to x = 0.2 are single phase. The bands of absorption in the 400– 500 cm-1 and the bands of absorption in the range of 500 -600 cm-1, corresponding to the formation of octahedral and tetrahedral sites which confirms the presence of metal– oxygen stretching band in ferrites. Also, SEM images show that by increasing Ni2+ doping grains size have been increased. However, for x > 0.2, the secondary Ni spinel ferrite (NiFe2O4) appears which the saturation magnetization and magnetic coercivity decreases. In addition, Ni2+substitution reduces the dielectric constant, dielectric loss, and ac electrical conductivity for all samples decrease rapidly with increasing applied field frequency and reaches a constant value beyond a certain frequency which this is characteristic of the normal dielectric behaviour of ferrites and has been investigated by Maxwell–Wagner’s two-layer model and Koop’s theory. The variation in ac conductivity (σac) with frequency shows that the electrical conductivity in these ferrites is mainly attributed to the electron hopping mechanism.Therefore; all single-phase Ni2+ substituted samples are suitable for use in magnetic recording media and microwave devices.


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