Pinning Effects on the Dielectric and Ferroelectric Properties of Mn-Doped Ba(Zr0.06Ti0.94)O3 Ceramics

2011 ◽  
Vol 687 ◽  
pp. 354-358 ◽  
Author(s):  
Shu Juan Kuang ◽  
Xin Gui Tang ◽  
Jun Bo Wu ◽  
Yan Ping Jiang ◽  
Qiu Xiang Liu
Keyword(s):  
Ferroelectric Properties ◽  
Orthorhombic Phase ◽  
X Ray Diffraction ◽  
Pinning Mechanism ◽  
X Ray ◽  
Defect Dipole ◽  
Uniform Microstructure ◽  
Lead Free Ceramics ◽  
Process Structure ◽  
Mn Doped

Lead-free ceramics with the composition of Mn-doped Ba(Zr0.06Ti0.94)O3 – xmol%MnO2 (BZT6-xMn, x=0, 1 and 2) have been synthesized by a mixed oxide process. Structure and micrograph characterization were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM), which revealed that all samples have the orthorhombic phase with dense and the uniform microstructure. The grain size of Mn-doped BZT6 ceramics decreased with increasing MnO2 doping. The effect of MnO2 doping on the dielectric and ferroelectric properties was also investigated. The maximum dielectric permittivity decreased dramatically with increasing MnO2 doping in the BZT6 ceramics. A peculiar double-hysteresis-like loop was observed. Mn ions as acceptor doping occupy the B site of ABO3 in the form of Mn2+ and Mn3+, which brought an increase in the oxygen vacancies concentration. The defect dipole model was explained the pinning mechanism.

Electrical Properties of Modified BNT Based Lead-Free Ceramics

2016 ◽  
Vol 872 ◽  
pp. 87-91
Author(s):  
Supalak Manotham ◽  
Tawee Tunkasiri ◽  
Pharatree Jaita ◽  
Pichitchai Butnoi ◽  
Denis Russell Sweatman ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Free Ceramics

The properties of modified Bi0.5Na0.5TiO3 (BNT) based lead-free ceramics were investigated. The BNT-based ceramics were prepared by a solid-state mixed oxide method Phase formation was determined by X-ray diffraction technique (XRD). The X-ray diffraction analysis of the ceramics suggested that all samples exhibited a perovskite structure without second phase. The value of dielectric constant increased with increasing in sintering temperature. Moreover, high sintering temperatures could improve ferroelectric properties of BNT base lead-free ceramics.

Effects of Donor Doping on Microstructure and Electrical Properties of Bismuth Layer-Structured Bi4Ti3O12 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 259-262 ◽  
Author(s):  
Lina Zhang ◽  
Su Chuan Zhao ◽  
Liao Ying Zheng ◽  
Guo Rong Li ◽  
Qing Rui Yin
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Electrical Properties ◽  
Ferroelectric Properties ◽  
Orthorhombic Phase ◽  
X Ray Diffraction ◽  
Suitable Candidate ◽  
X Ray ◽  
Donor Doping ◽  
Diffraction Patterns

A study was conducted on the effects of donor dopants, Nb2O5 and WO3, on microstructure and electric properties of Bi4Ti3O12 (BIT) ceramics. X-ray diffraction patterns of the materials showed a single orthorhombic phase structure. The microstructure results revealed the appearance of plate-like grain. The donor doping decreased the conductivity of BIT by as much as 3 orders of magnitude. The dielectric and ferroelectric properties of doped-BIT materials were also investigated. The decrease in the electrical conductivity allowed the doped samples to be poled to develop piezoelectricity. Thermal annealing studies of the samples indicated the donor-doped BIT were suitable candidate materials for high-temperature piezoelectric applications.

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.

DIELECTRIC AND FERROELECTRIC PROPERTIES OF (Li, Ce)-DOPED Sr2Bi4Ti5O18 LEAD-FREE CERAMICS

2011 ◽  
Vol 01 (04) ◽  
pp. 439-445 ◽  
Author(s):  
QIAN CHEN ◽  
ZHIJUN XU ◽  
RUIQING CHU ◽  
YONG LIU
Keyword(s):  
Electrical Properties ◽  
Single Phase ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
High Curie Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceramic Samples ◽  
Lead Free Ceramics ◽  
Ce Modification

The influence of (Li, Ce) doping on the electrical properties of bismuth layer Sr 2-x (Li, Ce) x/2 Bi4Ti5O18 [abbreviated to SBTi-(Li, Ce) X/2] ceramics was investigated. X-ray diffraction analysis showed that all the ceramic samples were single-phase compounds. The (Li, Ce) modification significantly decreased the dielectric loss of Sr2Bi4Ti5O18 ceramics and greatly improved the piezoelectric activity. At x/2 = 0.0125, the SBTi-(Li, Ce) x/2 ceramics exhibited the excellent properties with high remnant polarization (P r = 9.3 μC/cm2) and high Curie temperature (T c = 299°C). Meanwhile, the SBTi-(Li, Ce)0.0125 ceramics had the largest piezoelectric constant (d33 = 26 pC/N). The results showed that the SBTi-(Li, Ce) x/2 ceramic was a promising lead-free piezoelectric material.

Microdomains in BaFeO3-y (0.35 < y < 0.50)

1990 ◽  
Vol 48 (4) ◽  
pp. 780-781
Author(s):  
M. Vallet-Regí ◽  
M. Parras ◽  
J.M. González-Calbet ◽  
J.C. Grenier
Keyword(s):  
Electron Diffraction ◽  
Chemical Analysis ◽  
Monoclinic Phase ◽  
Orthorhombic Phase ◽  
Total Iron ◽  
Zone Axis ◽  
Electron Micrograph ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compositional Variations

BaFeO3-y compositions (0.35<y<0.50) have been investigated by means of electron diffraction and microscopy to resolve contradictory results from powder X-ray diffraction data.The samples were obtained by annealing BaFeO2.56 for 48 h. in the temperature range from 980°C to 1050°C . Total iron and barium in the samples were determined using chemical analysis and gravimetric methods, respectively.In the BaFeO3-y system, according to the electron diffraction and microscopy results, the nonstoichiometry is accommodated in different ways as a function of the composition (y):In the domain between BaFeO2.5+δBaFeO2.54, compositional variations are accommodated through the formation of microdomains. Fig. la shows the ED pattern of the BaFeO2.52 material along thezone axis. The corresponding electron micrograph is seen in Fig. 1b. Several domains corresponding to the monoclinic BaFeO2.50 phase, intergrow with domains of the orthorhombic phase. According to that, the ED pattern of Fig. 1a, can be interpreted as formed by the superposition of three types of diffraction maxima : Very strong spots corresponding to a cubic perovskite, a set of maxima due to the superposition of three domains of the monoclinic phase along [100]m and a series of maxima corresponding to three domains corresponding to the orthorhombic phase along the [100]o.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

Influence of LaNiO3 as an Electrode on the Properties of Ferroelectric Oxides

2000 ◽  
Vol 623 ◽  
Author(s):  
R. Kalare ◽  
M. Vedawyas ◽  
A. Kumar
Keyword(s):  
Ferroelectric Properties ◽  
Ferroelectric Thin Film ◽  
Memory Device ◽  
Epitaxial Films ◽  
Laser Deposition ◽  
Oxide Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potential Electrode ◽  
Ferroelectric Oxides

AbstractAn electrode plays an important role in realising a ferroelectric thin film as a potential memory device. We have investigated LaNiO3 (LNO) as a potential electrode material and evaluated the ferroelectric properties of oxide materials like strontium bismuth tantalate (SBT) and barium titanate(BT). We have successfully deposited epitaxial films of LNO on Pt coated Si(100) and LaAlO3 (LAO) substrates using the pulsed excimer laser deposition technique. We are able to grow high quality SBT and BT films on top of this LNO layer. The X-ray diffraction revealed the epitaxy of the LNO, SBT and BT films. The ferroelectric properties of SBTand BT were investigated using the RT66A ferroelectric tester.

scholarly journals Формирование и трансформация моноклинной и орторомбической фаз в реакторных порошках сверхвысокомолекулярного полиэтилена

2018 ◽  
Vol 60 (9) ◽  
pp. 1847
Author(s):  
М.В. Байдакова ◽  
П.В. Дороватовский ◽  
Я.В. Зубавичус ◽  
Е.М. Иванькова ◽  
С.С. Иванчев ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Room Temperature ◽  
Monoclinic Phase ◽  
Orthorhombic Phase ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Polymer Synthesis ◽  
X Ray Diffraction ◽  
Reactor Powder ◽  
X Ray ◽  
The One

AbstractUsing powerful synchrotron X-ray radiation of the beamline “Belok” operated by the National Research Center “Kurchatov Institute,” we perform X-ray diffraction (XRD) study of an intact, virgin (not subjected to any external mechanical loads) particle isolated from reactor powder of ultrahigh molecular weight polyethylene. Along with the peaks originating from the orthorhombic phase, we detect the peaks characteristic of the monoclinic phase that is stable only under mechanical stress, suggesting that the mechanical stress that leads to the formation of the monoclinic phase and persists at room temperature develops during the polymer synthesis. The monoclinic phase gradually disappears when the particle is heated stepwise in increments of 5 K, and its peaks become undetectable when the temperature reaches 340 K. We contrast the results obtained for the phase composition of the virgin particle to those for a tablet prepared by compaction of the same reactor powder at room temperature. XRD analyses of the tablet were performed on D2 Phaser (Bruker) instrument. The monoclinic phase that originates during the polymer synthesis and the one that forms in the tablet during compaction have different parameters. We discuss the mechanisms by which these two different monoclinic phases originate during the processes involved.

scholarly journals X-ray diffraction analysis of the non-uniform microstructure of rapidly solidified AlSi alloys

1981 ◽  
Vol 37 (a1) ◽  
pp. C153-C153
Author(s):  
R. Delhez ◽  
Th. H. de Keijser ◽  
E. J. Mittemeijer ◽  
P. van Mourik ◽  
N. M. van der Pers
Keyword(s):  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uniform Microstructure ◽  
Rapidly Solidified

Fabrication and Microstructure of Ge-Sb-S-CsCl Chalcogenide Glass Containing β-GeS2 Nanocrystals

2014 ◽  
Vol 665 ◽  
pp. 119-123
Author(s):  
Ji Yan Hao ◽  
Hai Tao Liu
Keyword(s):  
Chalcogenide Glass ◽  
Spherical Shape ◽  
Orthorhombic Phase ◽  
Far Infrared ◽  
X Ray Diffraction ◽  
Base Glass ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared Spectral ◽  
Quenching Method

we report the fabrication and microstructure of Ge-Sb-S-CsCl chalcogenide glass containing β-GeS2 nanocrystals. A Ge-Sb-S-CsCl chalcogenide base glass with the better crystalline ability is first fabricated by melt-quenching method, and a further careful thermal process has led to the formation of β-GeS2 nanocrystals in the glass. Transmission electron microscopy showed that the size of β-GeS2 nanocrystals with nearly monodisperse spherical shape ranges from 30 to 45 nm in the glass. Powder X-ray diffraction results confirm that the β-GeS2 nanocrystals are of high crystallization with orthorhombic phase. Energy dispersive spectroscopy is employed for the information of nanocrystals glass composition. It is worthwhile to note that the obtained Ge-Sb-S-CsCl chalcogenide glass containing β-GeS2 nanocrystals still keeps higher transmittance in mid- and far- infrared spectral region.

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