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Single-phase bismuth layered structure ferroelectromagnet (BLSFEM) LaGdxB5-xFe2Ti3O18of composition (x = 0.1, 0.2, 0.4, 0.6 and 0.8), novel ceramics were prepared by solid state route. Electrical and impedance measurements were made on the ceramics. Complex Impedance spectroscopic plots showed the signature of magnetic ion (Gd) and the results were corroborated to the Debye and Gaussian fitting curves. The variation of dielectric and modulus with temperature plots were used to explain dielectric phenomenon. An attempt is made to understand the effect of magnetic (Gd) ion on A site of (Bi2O2)2+(LaGdxBi3-xTi3Fe2O16)2−, layered perovskite (title) compound. [ABSTRACT FROM AUTHOR]

Novel polycrystalline materials of bismuth substituted barium titanate, namely, BaBixTi1-xO3-δ, (x = 0.025, 0.075, 0.125 and 0.175) was prepared by sol-gel chemical route and characterized by X-ray diffraction and scanning electron microscopy. Bismuth ion was added in place of titanium of B-site of ABO3 perovskite structure and both the site-balance as well as charge-balance was considered. The substitution of bismuth for Ti-site is clearly seen in both the XRD as well as IR spectroscopic data. Dielectric and impedance analysis were also made on the present novel ceramics. The above mentioned substitution involves ionic compensation, through creation of cation vacancies and is explained by proposing the defect dynamics. The results were corroborated with dielectric and complex impedance analysis for further understanding of ionic motion in this kind of disordered diffused materials. [ABSTRACT FROM AUTHOR]

Tri-Valent (Sm3+/ Dy3+) and pentavalent (Nb5+) modified polycrystalline material of Aurivillius family, namely R0.75Bi3.25Ti2.9625.Nb0.03O12 (R = Sm, Dy), were prepared by conventional solid-state reaction method. Impedance and pyroelectric measurements were carried out to understand the electrical properties of the samples. Master plots were drawn to understand the defect role, especially vacancies, and the results were corroborated with the dc-conductivity data. Finally, both the complex impedance spectroscopic as well as pyroelectric results were compared with the impedance data of technological important materials, namely La0.75Bi3.25Ti3O12 (BLT) and lead zirconium titanate (PZT) for the further understanding of defects and its effects at the grain interfaces. [ABSTRACT FROM AUTHOR]

Nano particulate Barium Bismuth Titanate (BaBixTi1-xO3-δ) materials with (x = 0.25, 0.075. 0.125 and 0.175) were prepared through sol-gel chemical route (Pichini method) and the XRD patterns were indexed on the basis of tetragonal-BaTiO3 phase. The electrical impedance measurements were carried out on the samples by using Auto Lab PGSTAT30 impedance analyzer in the frequency region 100 Hz-1 MHz from RT to 500°C. Impedance spectroscopic and complex explicit plots show the presence of both bulk and grain boundary effects, and impedance spectroscopy is shown to be an efficient method capable of detecting the conductivity species and estimating the electrical conductivity as well as activation energy value. Finally, the results are interpreted in terms of the defect dynamics and conduction mechanisms taking place in the samples. [ABSTRACT FROM AUTHOR]

Tri (Dy3 +) and pentavalent (Nb+5) modified new polycrystalline material of Aurivillius family (Dy0.75Bi3.25Ti2.9625Nb0.03O12) was prepared by solid-state reaction method and the lattice parameters were calculated by using X-ray diffractogram. Impedance measurements were carried out from room temperature to 500°C in the frequency range of 100 Hz to 1 M Hz. Impedance spectroscopic plots show non-Debye type and detailed ac-conductivity analysis was also employed to understand the heterogeneity of the present electro-ceramics. The results were corroborated with the proposed defect formula and in addition, thermal stimulated current measurements show that the present sample has an excellent pyroelectric response. [ABSTRACT FROM AUTHOR]

Impedance spectroscopic measurements were carried out on lead based ferroelectric ceramics, namely PZT, PLZT and PMN-PT, in the frequency range of 0.1 Hz-1 MHz. Spectroscopic plots showed broad peaks, and are found to shift towards higher frequency side. Apart from this, both Z'' and M'' spectroscopic peaks are found to coincide almost in the same frequency region. This indicates approximated-Debye behavior. Frequency dependent conductivity plots show two slopes at lower and higher frequency regions. Low frequency relaxations are found to be non-exponential. Bulk relaxation vs. temperature plots are found to obey Arhenius linear fit. The relaxation at lower frequency and higher are attributed to Kohlrausch-Williams-Watt (KWW) type and migration of slow oxygen and lead vacancies. The results are corroborated to the conduction barrier hopping mechanism and new Eyraud's conductivity model. [ABSTRACT FROM AUTHOR]

A and B site modified new bismuth layered structure ferroelectric ceramics of the Aurivillius family were prepared by the solid-state route. Impedance measurements were performed on these samples to understand the relaxation effects in the frequency range of 100 Hz to 1 MHz. From the detailed impedance and modulus spectroscopic analysis, it is found that the aliovalent modified B-site enhances the relaxor-like nature, compared to A-site substitution. These results were corroborated with ac-conductivity transport analysis. In this connection, a defect formula is also proposed. The results are discussed. [ABSTRACT FROM AUTHOR]

GdBi[sub 5]Fe[sub 2]Ti[sub 3]O[sub 18] (GBFT), a compound of Aurivillius family, was prepared by solid state reaction method. Complex impedance measurement was made on these samples from room temperature to 500°C in the frequency range of 1 kHz-1 MHz. Cole-Cole plots were found to become very broad near 400°C. Dielectric and dc conductivity measurements were made on these samples. The results are analysed to understand the conductivity mechanism. [ABSTRACT FROM AUTHOR]