A-Site Substituted BaTiO3: Analysis of Structural, Optical, Ferroelectric and Dielectric Nature

2020 ◽  
pp. 2050004
Author(s):  
Madhuri Soni ◽  
M. Saleem ◽  
Ashutosh Mishra
Keyword(s):  
Earth Metal ◽  
Dielectric Materials ◽  
Solid State Reaction Method ◽  
Optical Bandgap ◽  
X Rays ◽  
X Ray Diffraction ◽  
Low Loss ◽  
Polarization Effects ◽  
A Site ◽  
Fesem Micrographs

The well-known ferroelectric and dielectric materials based on barium titanate (BaTiO3) with the compositional formula Ba[Formula: see text]AEMxTiO3 [[Formula: see text] and AEM (alkaline earth metal) [Formula: see text] Ca and Sr] denoted as BTO, BCTO and BSTO are reported in this work. The solid-state reaction method was used to synthesize these titanates. The as-synthesized samples were characterized for structural elucidation via X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Raman inelastic scattering, energy dispersive analysis of X-rays (EDAX) and field emission scanning electron microscopy (FESEM). In addition to this, the samples were studied for optical bandgap, dielectric constant, dielectric loss, ac conductivity and polarization ([Formula: see text]–[Formula: see text]) studies. The XRD data analysis revealed that all the samples have acquired a tetragonal structure (P4mm) and are single phased. The Rietveld refinement of Ba[Formula: see text]Ca[Formula: see text]TiO3 confirms XRD results. In FTIR spectra, the absorption modes appearing at about 400[Formula: see text]cm[Formula: see text] and 500[Formula: see text]cm[Formula: see text] are attributes of the vibration of Ti–O bonds and Ba–O bonds, confirming the formation of desired samples. The appearance of the Raman mode of vibration at about 310[Formula: see text]cm[Formula: see text] is an indication of the tetragonal phase. FESEM micrographs of Ba[Formula: see text]Ca[Formula: see text]TiO3 reveal grain growth in the range of about 1[Formula: see text][Formula: see text]m and its EDAX spectrum confirms the composition of the sample. The optical bandgap was found to be 3.35[Formula: see text]eV, 3.1[Formula: see text]eV and 2.65[Formula: see text]eV for pristine, Ca[Formula: see text]- and Sr[Formula: see text]-doped BaTiO3, respectively. Frequency-dependent dielectric studies infer the samples to be extremely good dielectrics in nature with very low loss values. Polarization against a field at 1000[Formula: see text]V witnesses the samples to exhibit low polarization effects with lossy character. The dielectric and [Formula: see text]–[Formula: see text] behavior of Ba[Formula: see text]Sr[Formula: see text]TiO3 was found exceptional among all the reported titanates.

Lanthanum tetrazinc, LaZn4

2012 ◽  
Vol 68 (6) ◽  
pp. i37-i40 ◽  
Author(s):  
Igor Oshchapovsky ◽  
Volodymyr Pavlyuk ◽  
Grygoriy Dmytriv ◽  
Alexandra Griffin
Keyword(s):  
Rare Earth ◽  
Diffraction Data ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Structure Type ◽  
Alkaline Earth Metal ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Site ◽  
First Time

The structure of lanthanum tetrazinc, LaZn4, has been determined from single-crystal X-ray diffraction data for the first time, approximately 70 years after its discovery. The compound exhibits a new structure type in the space groupCmcm, with one La atom and two Zn atoms occupying sites withm2msymmetry, and one Zn atom occupying a site with 2.. symmetry. The structure is closely related to the BaAl4, La3Al11, BaNi2Si2and CaCu5structure types, which can be presented as close-packed arrangements of 18-vertex clusters, in this case LaZn18. The kindred structure types contain related 18-vertex clusters around atoms of the rare earth or alkaline earth metal.

Effect of Dy-doping on the microstructure and magnetic properties of Y1−xDyxMnO3

2013 ◽  
Vol 28 (S1) ◽  
pp. S45-S49 ◽  
Author(s):  
A.M. Zhang ◽  
G.T. Zhou ◽  
J. Sun ◽  
T. Xu ◽  
L.L. Guo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Rietveld Method ◽  
Solid State Reaction Method ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Spin Order ◽  
Cell Parameters ◽  
A Site ◽  
Dy Doping ◽  
Microstructure And Magnetic Properties

The effect of Dy3+ doping at A-site in hexagonal YMnO3 on the microstructure and magnetic properties was studied. Polycrystalline Y1−xDyxMnO3 samples with x ranging from 0 to 1 were synthesized by the solid-state reaction method. The microstructures of all the samples were studied by X-ray diffraction, which shows that Y1−xDyxMnO3 with a low concentration (x ≤ 0.5) of Dy3+ retains a hexagonal symmetry. The crystal structure refinements of the hexagonal Y1−xDyxMnO3 using the Rietveld method show that the unit-cell parameters of a, c, and unit-cell volume increase with increasing Dy doping, while the MnO5 trigonal bipyramids remain almost unchanged. The remarkable increasing of magnetic moment at a low temperature with increasing the Dy3+ doping concentration is ascribed to the spin order of Dy3+ and the increasing Dy3+–Mn3+ coupling and Mn3+–O–O–Mn3+ interaction.

IN-SITU X-RAY DIFFRACTION STUDY OF FERROELECTRIC DOMAIN SWITCHING IN ORTHORHOMBIC NKN CERAMICS

2010 ◽  
Vol 03 (01) ◽  
pp. 31-34 ◽  
Author(s):  
DAVID A. HALL ◽  
FERIDOON AZOUGH ◽  
NICHOLA MIDDLETON-STEWART ◽  
ROBERT J. CERNIK ◽  
ROBERT FREER ◽  
...  
Keyword(s):  
Domain Switching ◽  
Transformation Strain ◽  
Solid State Reaction Method ◽  
High Energy ◽  
Ferroelectric Domain ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Patterns ◽  
Ferroelectric Hysteresis

The family of perovskite ferroelectrics based on sodium potassium niobate (NKN) ceramics exhibit useful piezoelectric properties and show potential for the replacement of conventional lead based piezoceramics. In the present study, iron-doped NKN ceramics were prepared by a solid state reaction method. Ferroelectric hysteresis measurements indicated that a remanent polarization value approaching 0.4Cm-2 could be obtained by poling under a continuous AC electric field with amplitude of 3 MV m-1. X-ray diffraction (XRD) patterns of these materials were recorded in transmission during poling, using high energy synchrotron X-rays with a wavelength of 1.55 × 10-11m. Changes in crystallographic texture were observed during poling as a result of 90° and 60°/120° domain switching. The strain due to ferroelectric domain switching in orthorhombic NKN is described in terms of the differences in transformation strain between different domain variants, with reference to the high temperature cubic lattice.

scholarly journals Synthesis and Characterizations of Barium (Ba2+) and Strontium (Sr2+) Doped Bi0.9La0.1FeO3 System

2021 ◽  
Author(s):  
Saleem Saleem ◽  
Nikita Karma ◽  
Netram Kaurav ◽  
H. S. Dagar
Keyword(s):  
Electronic Device ◽  
Relaxation Times ◽  
Impedance Analysis ◽  
Dielectric Materials ◽  
Solid State Reaction Method ◽  
Spectral Studies ◽  
X Ray Diffraction ◽  
Spectra Analysis ◽  
X Ray ◽  
Device Applications

Abstract We discuss synthesis and various characterizations of Bi0.9La0.1-x(Ba/Sr)xFeO3 [x =0,0.05] ceramics. We synthesized these ceramics by solid state reaction method and the samples so synthesized were characterized for structural elucidation exploiting X-ray diffraction technique. The XRD data on Rietveld refinement inferred that all the prepared samples have acquired monoclinic phase with space group CI. Morphology of the samples revealed highly grown grains with moderate grain boundary development carried out exploiting field emission scanning electron microscopy (FESEM) technique. The Energy dispersive analysis of X-ray diffraction (EDAX) spectra analysis confirmed that composition is retained with absence of any foreign impurity. UV-Vis spectral studies of these ceramics confirmed that optical bandgap value about 2.2 eV highly recommended in photocatalytic and opto-electronic device applications. Room temperature dielectric studies revealed that samples are extremely good dielectric materials retained even after 1MHz applied field. The main feature is the dielectric loss which is negotiable for their capability in the modern device applications. Impedance analysis reveals the samples exhibit distributed relaxation times and inherit non-Debye behavior revealed from the depressed semicircles whose centers does not lie on x-axis.

scholarly journals Dielectric and Piezoelectric Studies of Dysprosium Doped BZT-BCNT Perovskite Ceramic System for Sensors and Actuators Applications

2021 ◽  
Author(s):  
Koduri Ramam ◽  
Srivathsava Surabhi ◽  
Gurumurthy Sangam ◽  
Shilpa P M ◽  
Bindu K ◽  
...  
Keyword(s):  
Solid State Reaction Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Ceramic System ◽  
Sensors And Actuators ◽  
Oxygen Ions ◽  
Energy Harvesters ◽  
Microscopic Studies ◽  
A Site ◽  
Dy Doping

Abstract Perovskite structured Dy doped BZT-BCNT system has been investigated with variation of Dy doping through the solid-state reaction method. X-ray diffraction (XRD) and microscopic studies confirm the results in the rhombohedral stoichiometry without any secondary phases, and uniform grain growth, respectively. Tolerance factor and electronegativity also confirm the presence of Dy doping in BZT-BCNT ceramic system with a stable rhombohedral crystallinity forming vacancy sites for oxygen ions. Optimum piezoelectric properties in non-Pb piezoelectric ceramic systems were obtained due to trivalent donor Dy doping at A-site and pentavalent donor Nb at B-site are possible members for actuator and energy harvesters. Dielectric and piezoelectric studies signifying the rhombohedral perovskite behavior of this lead-free ceramic system confess that the proposed investigation could yield further potential piezoelectric sensors and actuators applicative futuristic studies.

scholarly journals Composition dependence of dielectric properties in Pb(Zn1∕3Nb2∕3)O3–PbTiO3–BaTiO3 (PZN–PT–BT) relaxor ferroelectric ceramics

2017 ◽  
Vol 07 (02) ◽  
pp. 1750008
Author(s):  
Qiang Gao ◽  
Li Jin ◽  
Yu Cui ◽  
Ye Zhao ◽  
Kun Yu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Composition Dependence ◽  
Solid State Reaction Method ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cation Disorder ◽  
Diffusion Phase ◽  
A Site

Perovskite solid solution ceramics of PZN–PT–BT with several compositions were synthesized by solid-state reaction method. X-ray diffraction results indicate pure perovskite structures for all samples. Dielectric measurements show that the implicit Ba(Zn[Formula: see text]Nb[Formula: see text])O3(BZN) composition could broaden the diffusion phase transition (DPT) peaks and lower the [Formula: see text] and [Formula: see text] values. The observed dielectric properties may be caused by the increased cation disorder due to the substitution of barium onto the A-site and titanium onto the B-site.

scholarly journals The influence of the partially europium substitution on the AC electrical properties of BiSr2CaCu2O6.5 ceramics

2019 ◽  
Vol 13 (4) ◽  
pp. 323-332 ◽  
Author(s):  
Zeynep Özdemir ◽  
Mehmet Kılıç ◽  
Yaşar Karabul ◽  
Seda Erdönmez ◽  
Orhan İçelli
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Earth Metal ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Dielectric ◽  
Fourier Transformed Infrared Spectroscopy ◽  
High Dielectric

In this work, EuxBi1-xSr2CaCu2O6.5 (where x = 0, 0.3, 0.5) samples were prepared by solid-state reaction method and sintered at 950?C for 24 h. The structural characterizations were done by X-ray diffraction, X-ray fluorescence, scanning electron microscope and Fourier transformed infrared spectroscopy. The thermal stability of the samples was also analysed by thermogravimetric TG and DTA measurements. It was shown that Eu0.5Bi0.5Sr2CaCu2O6.5 sample exhibited high dielectric constant and low dielectric loss relative to BiSr2CaCu2O6.5 material. Thus, the dielectric loss was lowered by heavy rare earth metal substitution on Bi-Sr-Ca-Cu-O ceramics while the dielectric constant still remained high. Temperature-dependent complex electrical modulus spectra obtained between 296 and 433K also revealed the temperature-activated relaxation process in the materials which can be attributed to the Maxwell-Wagner type polarization effect. Ultimately, it was suggested that the Eu0.5Bi0.5Sr2CaCu2O6.5 ceramics may have a promising potential for applications which require high dielectric constant with a low dielectric loss.

scholarly journals Synthesis of LN/Si Nanostructures Layer by LayerBased on Mach-Zehnder Modulator using Pulsed Laser Deposition

2021 ◽  
Author(s):  
Luma Z. Mohammed ◽  
Makram A Fakhri ◽  
A. K. Abass ◽  
Evan T. Salim
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Rays ◽  
X Ray Diffraction ◽  
Low Loss ◽  
Electro Optic ◽  
Mach Zehnder Modulator ◽  
Si Nanostructures ◽  
Highly Uniform

Abstract A Mach-Zehnder electro-optic modulator (EOM) was fabricated employing pulsed laser deposition (PLD) method. Lithium Niobate (LN) was bonded to silicon nanocrystal substrate such that a waveguide combined structures were obtained. The over-all Properties of prepared device were investigated. The formation of LN was ensured by the x-ray diffraction results were the formation of ∆ phase was confirmed by the diffraction of x-rays from the (012) and (302) diffraction plans. The AFM results reflect the formation of highly uniform nanostructured with maximum roughness of about 12.9 nm. The constructed device shows that the recent improvements in hybrid MZ modulators using pulse laser deposition PLD and different electro-optic material have shown low loss and wide modulation bandwidth.

Effect of cerium substitution on structural and impedance properties of 0.8Ba0.2(Bi0.5K0.5)TiO3lead free ceramic system

2016 ◽  
Vol 30 (06) ◽  
pp. 1650056
Author(s):  
M. N. V. Ramesh ◽  
K. V. Ramesh
Keyword(s):  
Impedance Analysis ◽  
Solid State Reaction Method ◽  
High Energy ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Lead Free Ceramics ◽  
A Site

Cerium-doped 0.8BaTiO3-0.2Bi[Formula: see text]K[Formula: see text]TiO3with composition 0.8Ba0.2(Bi[Formula: see text]K[Formula: see text])Ti[Formula: see text]Ce[Formula: see text]O3where x = 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 lead free ceramics were prepared by conventional solid state reaction method followed by high energy ball milling. X-ray diffraction studies confirm the tetragonal structure at room temperature for all the Ce-doped samples. Lattice parameters and density were increasing with increase of Ce doping. Frequency and temperature dependent dielectric studies were carried out and indicate that the dielectric constant and Curie temperature are decreasing with increasing of Ce doping. All the Ce-doped samples exhibiting diffused and dispersive phase transitions with degree of diffuseness ranging from 1.4 to 2 calculated from the modified Curie–Weiss law. Impedance studies confirms the temperature dependent non-Debye kind of relaxation process in the material. From the Cole–Cole plots measured at high temperatures, reveals that the grain effect in the all Ce-doped samples. Impedance analysis studies also support the X-ray diffraction and dielectric studies that occupation of Ce both at A-site and B-site for small values of Ce doping.

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

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