Synthesis, Impedance and Dielectric Studies of Double Doped Strontium Bismuth Niobate Ferroelectric Ceramics
TL;DR: Strontium bismuth niobate (SBN), K0.025Sr0.95Gd0.1Bi2Nb2O9 (KSGBN3)) ceramics were prepared by two stage solid s... as discussed by the authors.
Abstract: Strontium bismuth niobate (SrBi2Nb2O9 (SBN), K0.025Sr0.95Gd0.025Bi2Nb2O9 (KSGBN1), K0.05Sr0.9Gd0.05Bi2Nb2O9 (KSGBN2) and K0.1Sr0.8Gd0.1Bi2Nb2O9 (KSGBN3)) ceramics were prepared by two stage solid s...
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TL;DR: In this paper, the authors used the modified Curie-Weiss law to evaluate the relaxor behavior and the fitting result of the relaxation parameter λ ǫ = 1.4, which verifies their relaxor property.
Abstract: The Ba0.985La0.015Ti0.9Sn0.1O3 ceramic has been prepared by a cost-effective solid-state reaction method. Preliminary room-temperature X-ray diffraction indicates that the crystallization of the ceramic is good. Field Emission Scanning Electron Microscopy was used to study the microstructure of ceramic. X-ray photoelectron spectroscopy was used to characterize the oxygen vacancies. Dielectric properties and impedance spectroscopy reflected the characteristic of relaxor-type behavior. Modified Curie–Weiss law was used to evaluate the relaxor behavior. The fitting result of the relaxation parameter λ = 1.4, which verifies their relaxor property. Jonscher’s power law was used to analyze the behavior of alternating current conductivity. The Arrhenius law was used to calculate the relaxor activation-energy (Ea) and the conduction activation-energy (Ec). The fitting results show that the Ea and Ec are 1.1 and 1. 13 eV, respectively. These values demonstrate that the high-temperature relaxor behavior was attributed to the double ionized oxygen vacancies. The electric field versus polarization curve reflects the energy-storage property of it. The maximum recoverable energy-storage density is 2.14 J/cm3, and the energy-storage efficiency is 67.65%.
6 citations
TL;DR: In this article, the authors proposed a polymer/ceramic composites with high dielectric permittivity for use in microelectronics, capacitors and related fields.
Abstract: Materials with high dielectric permittivity are in demand due to their potential applications in microelectronics, capacitors and related fields. Polymer/ceramic composites, due to their improved p...
3 citations
TL;DR: Ferroelectric ceramic compositions were prepared via conventional solid-state route with high density (92-99%) establishing the sintering conditions as discussed by the authors, and the results showed that the resulting Ferroelectric ceramics were of high density.
Abstract: Ferroelectric ceramic compositions SrBi2–xYxNb2O9 (x = 0.0, 0.2, 0.4, 0.6 and 0.8) were prepared via conventional solid-state route with high density (92-99%) establishing the sintering conditions....
3 citations
TL;DR: A promising Aurivillius layered pervoskite ceramics, namely, the title compound has drawn interest in recent days owing to its figure of merit (magnetoelectric coupled properties).
Abstract: A promising Aurivillius layered pervoskite ceramics, namely, the title compound has drawn interest in recent days owing to its figure of merit (magnetoelectric coupled properties). General formula ...
3 citations
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TL;DR: The effective ionic radii of Shannon & Prewitt [Acta Cryst. (1969), B25, 925-945] are revised to include more unusual oxidation states and coordinations as mentioned in this paper.
Abstract: The effective ionic radii of Shannon & Prewitt [Acta Cryst. (1969), B25, 925-945] are revised to include more unusual oxidation states and coordinations. Revisions are based on new structural data, empirical bond strength-bond length relationships, and plots of (1) radii vs volume, (2) radii vs coordination number, and (3) radii vs oxidation state. Factors which affect radii additivity are polyhedral distortion, partial occupancy of cation sites, covalence, and metallic character. Mean Nb5+-O and Mo6+-O octahedral distances are linearly dependent on distortion. A decrease in cation occupancy increases mean Li+-O, Na+-O, and Ag+-O distances in a predictable manner. Covalence strongly shortens Fe2+-X, Co2+-X, Ni2+-X, Mn2+-X, Cu+-X, Ag+-X, and M-H- bonds as the electronegativity of X or M decreases. Smaller effects are seen for Zn2+-X, Cd2+-X, In2+-X, pb2+-X, and TI+-X. Bonds with delocalized electrons and therefore metallic character, e.g. Sm-S, V-S, and Re-O, are significantly shorter than similar bonds with localized electrons.
51,997 citations
TL;DR: In this article, the Scherrer constants of simple regular shapes have been determined for all low-angle reflections (h2 + k2 + l2 ≤ 100) for four measures of breadth.
Abstract: Existing knowledge about Scherrer constants is reviewed and a summary is given of the interpretation of the broadening arising from small crystallites. Early work involving the half-width as a measure of breadth has been completed and Scherrer constants of simple regular shapes have been determined for all low-angle reflections (h2 + k2 + l2 ≤ 100) for four measures of breadth. The systematic variation of Scherrer constant with hkl is discussed and a convenient representation in the form of contour maps is applied to simple shapes. The relation between the `apparent' crystallite size, as determined by X-ray methods, and the `true' size is considered for crystallites having the same shape. If they are of the same size, then the normal Scherrer constant applies, but if there is a distribution of sizes, a modified Scherrer constant must be used.
3,018 citations
TL;DR: In this article, the authors describe the preparation and characterization of thin-film capacitors using ferroelectric materials from a large family of layered perovskite oxides, exemplified by SrBi2Ta2O9, SRBi2NbTaO9 and SrBi4Ta4O15.
Abstract: A SIGNIFICANT fraction of the computer memory industry is at present involved in the manufacture of non-volatile memory devices1—that is, devices which retain information when power is interrupted. For such applications (and also for volatile memories), the use of capacitors constructed from ferroelectric thin films has stimulated much interest1. In such structures, information is stored in the polarization state of the ferroelectric material itself, which should in principle lead to lower power requirements, faster access time and potentially lower cost1. But the use of ferroelectrics is not without problems; the memories constructed to date have generally suffered from poor retention of stored information and degradation of performance ('fatigue') with use1–3. Here we describe the preparation and characterization of thin-film capacitors using ferroelectric materials from a large family of layered perovskite oxides, exemplified by SrBi2Ta2O9, SrBi2NbTaO9 and SrBi4Ta4O15. The structural flexibility of these materials allows their properties to be tailored so that many of the problems associated with previous ferroelectric memories are avoided. In particular, our capacitors do not show significant fatigue after 1012 switching cycles, and they exhibit good retention characteristics and low leakage currents even with films less than 100 nm thick.
2,378 citations
TL;DR: In this paper, the critical exponent γ in the relation between the dielectric constant and temperature (1/e − 1/em = C'-1x (T −Tm)γ) has been determined precisely for relaxor ferroelectrlics Pb(Mg1/3Nb2/3)O3, and a related solid solution 0.88Pb (Zn 1/3 Nb 2/3)-O3-0. I2PbT103.
Abstract: The critical exponent γ in the relation between the dielectric constant and temperature (1/e—1/em = C'-1x (T—Tm)γ) has been determined precisely for relaxor ferroelectrlics Pb(Mg1/3Nb2/3)O3, Pb(Zn1/3 Nb2/3)O3 and a related solid solution 0.88Pb (Zn1/3 Nb2/3)O3-0. I2PbT103, as well as for normal ferroelectrics BaTiO3 and K(Ta0. 55Nb0.45)O3. A high correlation of the γ value with the plase transition diffuseness has been found empirically. Moreover, this γ value is very close to another critical exponent γ* which is defined in the relation between the dielectric constant and hydrostatic pressure (1/e—1/em = C* (p—pm)γ*)
1,102 citations
TL;DR: In this paper, a dielectric study revealed ferroelectricity in the following compounds: MeBi2R2O2 (Me Ba,Pb, Sr and R ǫ Nb, Ta), MeBi4TiNbO9 (Me 0.5Bi4.5), Me0.5Ti4O15 (Me, K, Na), Me2Bi4O5O18 (Me, Pb, S), Me 0.
919 citations