Ferroelectric characteristics of Fe/Nb co-doped BaTiO3

2019 ◽  
Vol 33 (22) ◽  
pp. 1950261
Author(s):  
Mukhlis M. Ismail
Keyword(s):  
Dielectric Permittivity ◽  
Solid Phase ◽  
Ferroelectric Properties ◽  
Peak Shift ◽  
Energy Storage Materials ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Shift Effect ◽  
Sintering Method ◽  
Co Doped

[Formula: see text] ceramics ([Formula: see text] mol.%, [Formula: see text]:[Formula: see text] = 1:3, 2:3, 3:2, 3:1) were successfully prepared using the traditional solid-phase sintering method. The effects of the proportion doping (Fe/Nb) components on various properties of BaTiO3 ceramics were studied. The X-ray diffraction showed that all solid solutions have the single cubic phase at room temperature, and that dielectric permittivity exhibits a maximum, Curie’s temperature at the peak. The ceramics have obvious peak shift effect: Curie’s temperature shifts to low temperature as Fe/Nb ratio increases. The high Fe/Nb ratio BaTiO3 ceramic showed also an enhancement of the broadening effect for dielectric constant curve with respect to temperature, and dielectric permittivity peak reflected phase transition from rhombohedral to tetragonal polar-nano regions. Dielectric and ferroelectric properties of Fe/Nb co-doped BaTiO3 ceramics have obvious enhanced ferroelectric properties and have slender hysteresis loop beneficial for energy storage materials.

Stacking Faults in a High Nitrogen Face-Centered-Cubic Phase Formed on Nitrogen-Modified Austenitic Stainless Steel

2008 ◽  
Vol 373-374 ◽  
pp. 318-321
Author(s):  
J. Liang ◽  
M.K. Lei
Keyword(s):  
Stainless Steel ◽  
Plasma Source ◽  
Peak Shift ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
High Nitrogen ◽  
X Ray ◽  
Peak Asymmetry ◽  
Face Centered

Effects of stacking faults in a high nitrogen face-centered-cubic phase (γΝ) formed on plasma source ion nitrided 1Cr18Ni9Ti (18-8 type) austenitic stainless steel on peak shift and peak asymmetry of x-ray diffraction were investigated based on Warren’s theory and Wagner’s method, respectively. The peak shift from peak position of the γΝ phase is ascribed to the deformation faults density α, while the peak asymmetry of the γΝ phase is characterized by deviation of the center of gravity of a peak from the peak maximum (Δ C.G.) due to the twin faults density β. The calculated peak positions of x-ray diffraction patterns are consistent with that measured for plasma source ion nitrided 1Cr18Ni9Ti stainless steel.

scholarly journals Modulation of Ferroelectric and Optical Properties of La/Co-Doped KNbO3 Ceramics

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2273
Author(s):  
Xue Zhang ◽  
Ruijuan Qi ◽  
Shangwei Dong ◽  
Shuai Yang ◽  
Chengbin Jing ◽  
...  
Keyword(s):  
Ferroelectric Properties ◽  
Cubic Phase ◽  
Bandgap Engineering ◽  
La Doping ◽  
Co Doping ◽  
Extrinsic Defect ◽  
Potential Applications ◽  
Defect Levels ◽  
Microscopic Morphology ◽  
Co Doped

The phase transition, microscopic morphology and optical and ferroelectric properties are studied in a series of La- and Co-doped KNbO3-based ceramics. The results show that the doping induces the transformation from the orthorhombic to the cubic phase of KNbO3, significantly reduces the optical bandgap and simultaneously evidently improves the leakage, with a slight weakening of ferroelectric polarization. Further analysis reveals that (i) the Co doping is responsible for the obvious reduction of the bandgap, whereas it is reversed for the La doping; (ii) the slight deterioration of ferroelectricity is due to the doping-induced remarkable extrinsic defect levels and intrinsic oxygen vacancies; and (iii) the La doping can optimize the defect levels and inhibit the leakage. This investigation should both provide novel insight for exploring the bandgap engineering and ferroelectric properties of KNbO3, and suggest its potential applications, e.g., photovoltaic and multifunctional materials.

scholarly journals ENHANCED FERROELECTRICITY AND FERROMAGNETISM OF (Y, Ni) CO-DOPED BiFeO3 MATERIALS

2018 ◽  
Vol 56 (1A) ◽  
pp. 219
Author(s):  
Dao Viet Thang
Keyword(s):  
Ferroelectric Properties ◽  
Sol Gel ◽  
Rhombohedral Structure ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Saturation Polarization ◽  
Perovskite Type ◽  
Co Doped

In this study, multiferroicMultiferroic Bi1-xYxFe0.975Ni0.025O3 (x = 0.00, 0.05, 0.10, and 0.15) called as (Y, Ni)                co-doped BiFeO3 materials were synthesized by a sol-gel method.  and characterized by X-ray diffraction diagrams and(XRD), energy-dispersive X-ray (EDX) and vibrating sample magnetization (VSM) measurements demonstrated. The result showed that Bi1-xYxFe0.975Ni0.025O3all investigated materials waspresent a single phase of the perovskite-type rhombohedral structure. Ferromagnetism and ferroelectricity of the Bi1-xYxFe0.975Ni0.025O3 materials have been investigated. Results showed that the co-doping by (Y, Ni) for (Bi, Fe)  have affected in enhancing by the (Y, Ni) co-doping, as a result the ferroelectric polarization and magnetization of BiFeO3. The magnetic characterization indicated that the ferromagnetic behavior wasthe initial BiFeO3 materialwere enhanced with increasing concentration of Y3+ for (Y, Ni) co-substituted of BiFeO3. Which could beion. It is attributed to the defferentdifference of the magnetic momentmoments of Ni2+ and Fe3+, and+ ions, as well as the Y3+-Fe3+,+ and Y3+-Ni2+ super-exchange interaction. Theinteractions. The characteristics of the investigated materials, such as remanent magnetization (Mr), saturation magnetization (Ms), remanent polarization (2Pr) and saturation polarization (2Ps) continuously increase upon increasing in the range of x from 0.00 to 0.15. When x = 0.15, the values of Mr and Ms are 0.078 and 0.794 emu/g, respectively. The values of 2Pr and 2Ps are 16.58 and 27.99 µC/cm2, respectively. Origin of ferromagnetic and ferroelectric properties of Bi1-xYxFe0.975Ni0.025O3 materials will be discussed in this paper.

STUDY ON ABNORMAL PHENOMENON ABOUT ENHANCED ELECTRICAL CONDUCTIVITY OF Bi1-xBaxFeO3 CERAMICS

2014 ◽  
Vol 28 (05) ◽  
pp. 1450009 ◽  
Author(s):  
H. J. WANG ◽  
S. Y. WANG ◽  
W. F. LIU ◽  
X. J. XI ◽  
FENG GUO ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Solid Phase ◽  
Electrical Conductance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multiferroic Properties ◽  
Abnormal Phenomenon ◽  
Sintering Method

In order to investigate the effects of Ba doping BiFeO 3 on multiferroic properties, Bi 1-x Ba x FeO 3(0≤x≤1)( Ba x BFO ) ceramics were fabricated via rapid solid phase sintering method, and material's structures and electrical properties were investigated. The phase transitions from rhombohedral to pseudo-cubic (x = 10%) and then to tetragonal (x = 40%) were confirmed by X-ray diffraction investigation. Although the electrical conductivity of Ba x BFO (x = 10%, 20% and 30%) ceramics was low, which is a similar trend to previous reports, an abnormal enhancement of electrical conductance was observed in Ba x BFO (x = 1%, 3% and 5%) ceramics. Such as, the electrical conductivity of Ba 0.03 BFO is calculated to be ~106 Ω⋅ cm that is five orders of magnitude higher than that of the BiFeO 3. This has been discussed and ascribed to more percent of oxygen vacancies and Fe 2+ ions in Ba x BFO ceramics, as confirmed by X-ray photoelectron spectroscopy investigation.

Effects of Eu and Ca Co-Substitution for the Improvement of Multiferroic Properties of BiFeO3

2016 ◽  
Vol 697 ◽  
pp. 288-292
Author(s):  
Xin Xu ◽  
Qi Fu Yao ◽  
Sheng Peng ◽  
Long Kai Fang ◽  
Wei Wei Mao ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spin Structure ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Structure Transition ◽  
X Ray ◽  
Multiferroic Properties ◽  
Co Doped

Pure BiFeO3 (BFO), Ca-doped and Eu/Ca-codoped BFO nanoparticles were prepared by using a sol–gel method. The effects of Eu/Ca-codoped on the structural, magnetic and ferroelectric properties of the samples were studied. The X-ray diffraction (XRD) analysis reveals a structure transition in the codoped samples. Co-doped samples were obtained with the best ferromagnetic properties, with the largest remaining magnetization Mr = 0.20 emμ/g. The structure transition may be the main cause for the origin of improved magnetic properties, which destroys the space modulated spin structure of BFO and releases the locked magnetic. In addition, the doping of Eu into BFO can reduce the leakage current and enhance the ferroelectric properties.

scholarly journals USE OF DUST X-RAY DIFFRACTION IN THE CHARACTERIZATION OF PEROVSKITAS TYPE FERRITES

2008 ◽  
Vol 05 (9) ◽  
pp. 23-30
Author(s):  
Márcio DE PAULA ◽  
Regina Helena Porto FRANCISCO
Keyword(s):  
Solid State ◽  
Powder Diffraction ◽  
Structural Changes ◽  
Solid Phase ◽  
Orthorhombic Phase ◽  
Polycrystalline Sample ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray

The X-ray diffraction is one experimental method very important on characterization solids compounds. In the case of polycrystalline samples, the x-ray powder diffraction allows for the identification of the solid phase and the characterization of structural changes. The present paper was prepared any antiferromagnetic ceramic phases, bicalcic ferrite derivate (Ca2Fe2O5) by solid state reaction from pulverized reagents and mixed manually. These were heated in the Pt melting pan, in air oven at temperature between 1000 and 1450oC for 12h. The occurrence of reaction with reagents and the products obtained were identified and structurally characterized by X-ray diffraction by polycrystalline sample. Mixtures of regents CaCO3, SrCO3, BaCO3, Fe2O3, Nb2O5, Have been made with various symmetries: a) Ba2Fe2O5, b) CaBaFe2O5, c) Ba2FeNbO6, d) Ca2Fe2O5, (e) Ba2Nb2O7, (f) Ca2Nb2O7, (g) Sr2Nb2O7, (h) CaBaFeNbO6. The products obtained showed that O2 of the air participated of reactions by providing the anions oxides required for obtaining the cubic phase. The formation of this phase was also helped by the presence of barium and niobium, since in the absence of these elements, can be seen the formation of orthorhombic phase, characteristic of Ca2Fe2O5.

scholarly journals Ferroelectric Properties of CuFe2O4, BaFe2O4, Ba0.2La0.8Fe2O4 Nanoparticles

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
U. Naresh ◽  
R. Jeevan Kumar
Keyword(s):  
Barium Ferrite ◽  
Structural Parameters ◽  
Ferroelectric Properties ◽  
Orthorhombic Phase ◽  
Ferrite Nanoparticles ◽  
Cubic Phase ◽  
Copper Ferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polarization Electric Field

In this article, we report ferroelectric properties of copper ferrite CuFe2O4 nanoparticles (CFN), Barium ferrite nanoparticles BaFe2O4 (BFN) and La substituted barium ferrite Ba0.2La0.8Fe2O4 (BLFN) nanoparticles synthesized via hydrothermal technique. The X-Ray diffraction for the synthesized particles reflects the cubic phase formation for CuFe2O4, orthorhombic phase structure for the BaFe2O4 and cubic formation of Ba0.2La0.8Fe2O4 (BLFN). The structural parameters such as crystallite size and micro-strain are computed from XRD and Williamson-Hall(W-H) analysis. The polarization- electric field (P-E) loop studies gave information about the ferroelectric nature of the synthesized samples. It was noticed that the CFN particle has a lossy dielectric nature whereas BFN, BLFN samples exhibit a multiferroic nature.

Structure and Optical Thermometry Characterization of Er3+/Yb3+ Co-Doped BaGd2CuO5

2016 ◽  
Vol 16 (4) ◽  
pp. 3542-3546 ◽  
Author(s):  
Xiaodong Li ◽  
Yanjie Song ◽  
Yanmin Yang ◽  
Chao Mi ◽  
Yanzhou Liu ◽  
...  
Keyword(s):  
Solid Phase ◽  
Green Emission ◽  
Upconversion Emission ◽  
Phase Method ◽  
Excitation Density ◽  
Fluorescence Intensity Ratio ◽  
X Ray Diffraction ◽  
Solid Phase Method ◽  
Fir Technique ◽  
Co Doped

Er3+/Yb3+ co-doped BaGd2CuO5 upconversion luminescent materials are obtained by solid phase method. Rietveld refinement on X-ray diffraction data indicates that Er3+/Yb3+ ions are inclined to occupy the Gd(1) site in the structure of BaGd2CuO5 (green phase). Two green emission peaks located at 523 nm and 547 nm have been produced by the excitation of 971 nm LD. The fluorescence intensity ratio (FIR) of the two green emission peaks have been investigated in the temperature range of 290 K–594 K. The maximum sensitivity derived from the FIR technique of the green upconversion emission is approximately 0.0038 K−1, and it has a high transmission power at low excitation density. This result implies that the Er3+/Yb3+ co-doped BaGd2CuO5 phosphors can play an important role in temperature measurements with a better sensitivity.

scholarly journals On the Ferroelectric to Paraelectric Structural Transition of BaTiO3 Micro-/Nanoparticles and Their Epoxy Nanocomposites

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2686
Author(s):  
Georgia C. Manika ◽  
Konstantinos S. Andrikopoulos ◽  
Georgios C. Psarras
Keyword(s):  
Structural Transition ◽  
Ferroelectric Properties ◽  
Laser Raman Spectroscopy ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Raman ◽  
Broadband Dielectric Spectroscopy ◽  
Ceramic Components ◽  
Direct Results

BaTiO3 is one of the most widely used ceramic components in capacitor formulation due to its exceptional ferroelectric properties. The structural transition from the ferroelectric tetragonal to the paraelectric cubic phase has been studied in both nano- and micro-BaTiO3 particles. Several experimental techniques were employed for characterization purposes (X-ray diffraction-XRD, laser Raman spectroscopy-LRS, differential scanning calorimetry-DSC and broadband dielectric spectroscopy-BDS). All gave evidence for the structural transition from the polar tetragonal to the non-polar cubic phase in both nano- and micro-BaTiO3 particles. Variation of Full Width at Half Maximum (FWHM) with temperature in XRD peaks was employed for the determination of the critical Curie temperature (Tc). In micro-BaTiO3 particles (Tc) lies close to 120 °C, while in nanoparticles the transition is complicated due to the influence of particles’ size. Below (Tc) both phases co-exist in nanoparticles. (Tc) was also determined via the temperature dependence of FWHM and found to be 115 °C. DSC, LRS and BDS provided direct results, indicating the transition in both nano- and micro-BaTiO3 particles. Finally, the 15 parts per hundred resin per weight (phr) BaTiO3/epoxy nanocomposite revealed also the transition through the peak formation at approximately 130 °C in the variation of FWHM with temperature. The present work introduces, for the first time, a qualitative tool for the determination and study of the ferroelectric to paraelectric structural transition in both nano- and micro-ferroelectric particles and in their nanocomposites. Moreover, its novelty lies on the effect of crystals’ size upon the ferroelectric to the paraelectric phase transition and its influence on physical properties of BaTiO3.

scholarly journals Structure and Conductivity Studies of Scandia and Alumina Doped Zirconia Thin Films

Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 317 ◽  
Author(s):  
Mantas Sriubas ◽  
Nursultan Kainbayev ◽  
Darius Virbukas ◽  
Kristina Bočkutė ◽  
Živilė Rutkūnienė ◽  
...  
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Size Dependence ◽  
Cubic Phase ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Impedance Measurements ◽  
Raman Analysis ◽  
X Ray ◽  
Co Doped

In this work, scandia-doped zirconia (ScSZ) and scandia–alumina co-doped zirconia (ScSZAl) thin films were prepared by electron beam vapor deposition. X-ray diffraction (XRD) results indicated a presence of ZrO2 cubic phase structure, yet Raman analysis revealed the existence of secondary tetragonal and rhombohedral phases. Thus, XRD measurements were supported by Raman spectroscopy in order to comprehensively analyze the structure of formed ScSZ and ScSZAl thin films. It was also found that Al dopant slows down the formation of the cubic phase. The impedance measurements affirmed the correlation of the amount of secondary phases with the conductivity results and nonlinear crystallite size dependence.

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