Pure PZT95/5 ceramics and its phase transition behavior under external fields

2021 ◽  
Vol 01 ◽  
Author(s):  
Hengchang Nie ◽  
Fei Cao ◽  
Genshui Wang ◽  
Xianlin Dong
Keyword(s):  
Phase Transition ◽  
Hydrostatic Pressure ◽  
Ferroelectric Materials ◽  
Pulsed Power ◽  
External Fields ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Antiferroelectric Phase ◽  
Diffraction Patterns ◽  
Ferroelectric Hysteresis

Background: Compositionally modified Pb(Zr0.95Ti0.05)O3 (PZT 95/5) ferroelectric materials are extensively investigated in past decades for many important applications. However, few pure PZT95/5 ceramics were reported. Objective: Herein, pure PZT95/5 ceramics were successfully prepared and their microstructure, phase transition behaviors under external fields were studied. Method: Pure PZT95/5 ceramics were prepared by conventional solid state reaction using a mixed oxide route. The microstructure and its properties under different external fields were measured. Results: The X-ray diffraction patterns indicate that the virgin pure PZT95/5 ceramics exhibit an orthorhombic antiferroelectric phase, also evidenced by the superlattice reflections in SAED pattern. While a rhombohedral ferroelectric symmetry crystal structure was observed in the pooled samples suggesting that an electric field induced antiferroelectric to ferroelectric phase transition occured. Pure PZT95/5 ceramics exhibited a quenched ferroelectric hysteresis loop with a remnant polarization of ~8μC/cm2 under 3.5kV/mm. Temperature dependence dielectric response indicated that orthorhombic antiferroelectric to cubic paraelectric phase transition occured at 225oC, corresponding to its Curie temperature. A shard depolarization behavior and dielectric anomalies were observed under ~240 MPa hydrostatic pressure. Conclusions: The depolarization mechanism of pure PZT95/5 ceramics under hydrostatic pressure is attributed to the hydrostatic pressure induced FE-AFE phase transition. These results will offer fundamental insights into PZT95/5 ceramics for pulsed power supply applications.

Effects of ZnO Doping on Microstructure, Dielectric and Ferroelectric Properties of La2Ti2O7 Ceramics

2014 ◽  
Vol 602-603 ◽  
pp. 719-722
Author(s):  
Gang Chen ◽  
Xiao Dong Peng ◽  
Chun Lin Deng ◽  
Chun Lin Fu ◽  
Wei Cai ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Ferroelectric Properties ◽  
Solid State Reaction Method ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Dielectric Constant And Loss ◽  
Diffraction Patterns ◽  
Ferroelectric Hysteresis ◽  
Zno Doping

The La2Ti2O7+xwt%ZnO(x=0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were prepared by the conventional solid state reaction method, and effects of ZnO doped on the structure, dielectric and ferroelectric properties were investigated in detail. The X-ray diffraction patterns of La2Ti2O7ceramics doped by ZnO oxide showed that no second phase exists. The surface morphology is palte-like shape, the grains of La2Ti2O7ceramics increase with increasing the content of ZnO, and the result is to improve the density of La2Ti2O7ceramics. The dielectric constant and loss decreases with increasing frequency.When the content of ZnO is more than 0.05wt%, the dielectric constant and loss decreases with the amount of addition of ZnO oxide increasing. The ferroelectric hysteresis loop is not saturable, which is attributed to its large leakage current. The ferroelectric properties improve with the addition of ZnO oxide. .

Ferroelectric Properties of SBT doped with Pr

2004 ◽  
Vol 848 ◽  
Author(s):  
J. Mata ◽  
A. Durán ◽  
E. Martínez ◽  
J. M. Siqueiros ◽  
J. Heiras
Keyword(s):  
Long Range ◽  
Ferroelectric Properties ◽  
Ferroelectric Ceramic ◽  
Ferroelectric Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strong Pinning ◽  
Diffraction Patterns ◽  
Ferroelectric Hysteresis ◽  
Diffuse Phase

ABSTRACTThe Sr1-xPrxBi2Ta2O9 (SBT-Pr) ferroelectric ceramic doped with Praseodymium in the range of concentration between 0 and 0.20 was studied. X-ray diffraction patterns show that the Pr-ion substitutes the Sr-ion in the main structure (A21am space group) and, as a consequence of this substitution the unit cell decreases monotonically. Thermoelectric Analysis (ε vs T) and ferroelectric hysteresis measurements were performed. From the ε-T curves it was observed that the transition temperature depends almost linearly on Pr content. Broad phase transitions were also observed, a typical behavior of ferroelectric materials with diffuse phase transition (DPT). An increase in the diffuseness coefficient is obtained by increasing Pr content according to the Isupov model, due to the higher cationic disorder in the structure, resulting in the loss of the long-range ferroelectric ordering. The hysteresis loop indicates that the substitution of Sr2+ by Pr3+,4+ lowers the polarization due possible to strong pinning domain mechanisms that obstruct long range ferroelectric ordering.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

Phase Transition of C5H5 NHSbBr4 Having a Hypervalent Bond: A 2H NMR and X-Ray Diffraction Study [Phase Transition of C5H5NHSbBr4]

1996 ◽  
Vol 51 (5-6) ◽  
pp. 739-744
Author(s):  
K. Yamada ◽  
T. Ohtani ◽  
S. Shirakawa ◽  
H. Ohki ◽  
T. Okuda ◽  
...  
Keyword(s):  
Phase Transition ◽  
Nearest Neighbor ◽  
Study Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Deuterated Analog ◽  
Librational Motion ◽  
Diffraction Patterns

Abstract The second order phase transition at 253 K of pyridinium tetrabromoantimonate(III), C5H5NHSbBr4 , has been characterized by means of X-ray diffraction and 2H NMR. As was suggested from the 81Br NQR spectra, the Rietveld refinements of the X-ray diffraction patterns at 297 K and 116 K confirm the structural change of the anion from SbBr-4 to SbBr3 • Br-. The line shape analysis of the 2H NMR using the deuterated analog revealed that the librational amplitude of the pyridinium ring about the axis normal to the plane increased with temperature and its rms amplitude reaching ca. 25° at Tc . The librational motion may induce the phase transition breaking the hydrogen bonds of the type N-H … Br. However, nearest-neighbor 2π/6 jump or reorientation such as seen in benzene were not observed even at 350 K.

Magneto-dielectric anomaly in (Bi0.95Nd0.05)(Fe0.97Mn0.03)O3 electroceramic

2014 ◽  
Vol 1636 ◽  
Author(s):  
Shalini Kumari ◽  
Nora Ortega ◽  
Ashok Kumar ◽  
Ram S. Katiyar
Keyword(s):  
Dielectric Response ◽  
Analytical Data ◽  
Rhombohedral Phase ◽  
Dielectric Anomaly ◽  
Neel Temperature ◽  
X Ray Diffraction ◽  
Néel Temperature ◽  
Conventional Solid State Reaction ◽  
Diffraction Patterns ◽  
Small Chemical

ABSTRACTWe report magneto-dielectric anomaly of the multiferroic (Bi0.95Nd0.05)(Fe0.97Mn0.03)O3 (BNFM) ceramic near Néel temperature. The ceramic pellets were synthesized by conventional solid state reaction route. X-ray diffraction patterns revealed that most of the peaks shifted slightly towards higher Bragg’s angle compared to those of pure BiFeO3 and also confirmed the formation of rhombohedral phase. It also suggests that the small chemical substitution of Nd and Mn atoms at Bi and Fe sites of BiFeO3 (BFO) perovskite respectively does not alter the crystal structure. Temperature and frequency dependent dielectric response indicate large dielectric anomaly at 620 K, slightly below the known Néel temperature of BFO. The enhancement in dielectric properties of BNFM ceramic was observed as compared to BFO due to suppression of oxygen vacancies by the doping. Temperature dependent dielectric response in conjunction with Raman and thermo-analytical data show that the BNFM sample presents significant magneto-dielectric response around Néel temperture TN ∼ 620 K.

Investigations on Dielectric phase transition behavior of Pb(Fe0.5-xScx)Nb0.5O3 Multiferroic Ceramics

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 585-590
Author(s):  
Bandi Mallesham ◽  
Ranjith Ramadurai
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Essential Feature ◽  
Low Frequency ◽  
Cation Ordering ◽  
X Ray Diffraction ◽  
Dielectric Phase ◽  
Diffraction Patterns ◽  
The Stability

ABSTRACTPhase pure Pb[(Fe0.5-xScx)Nb0.5]O3 [x = 0 to 0.5] multiferroic relaxors have been synthesized to study the effect of Sc on dielectric phase tansition. Rietveld refinement of x-ray diffraction patterns confirm that the structure transforms from monoclinic (Cm) to rhomobohedral (R3m) at x = 0.3. Absence of low frequency dielectric response in compositions with low Sc content attributed to interfacial polarizabilty arising due to differences in conductivities of grain and grain boundary. Moreover, value of diffusivity parameter (γ) of high of Sc content compositions is near to 2, confirms relaxor charactertistic of these compositions. However, an essential feature of relaxors i.e., frequency dependent dielectric permittivity as a function of temperature is observed only in x = 0.5 composition [Pb(Sc0.5Nb0.5)O3 (PSN)]. In addition, ferroelectric phase transition temperature (Tmax) increases initially at lower Sc content (upto x ≤ 0.25), and further drops beyond x ≥ 0.3. Such behavior of Tmax in these compositions is due to the onset of B'-B" local cation ordering at x = 0.3. High temperature Raman spectra of Pb(Sc0.5Nb0.5)O3 (x = 0.5) confirm the stability of cation ordering in compositions with high Sc content well above the phase transition temperature.

Barium hollandite-type compounds BaxFe2xTi8−2xO16 with x=1.143 and 1.333

1999 ◽  
Vol 14 (1) ◽  
pp. 31-35 ◽  
Author(s):  
J. M. Loezos ◽  
T. A. Vanderah ◽  
A. R. Drews
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Powder Diffraction ◽  
Framework Structure ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns ◽  
Acta Crystallogr

Experimental X-ray powder diffraction patterns and refined unit cell parameters for two barium hollandite-type compounds, BaxFe2xTi8−2xO16, with x=1.143 and 1.333, are reported here. Compared to the tetragonal parent structure, both compounds exhibit monoclinic distortions that increase with Ba content [Ba1.333Fe2.666Ti5.334O16: a=10.2328(8), b=2.9777(4), c=9.899(1) Å, β=91.04(1)°, V=301.58(5) Å3, Z=1, ρcalc=4.64 g/cc; Ba1.143Fe2.286Ti5.714O16: a=10.1066(6), b=2.9690(3), c=10.064(2) Å, β=90.077(6)°, V=301.98(4) Å3, Z=1, ρcalc=4.48 g/cc]. The X-ray powder patterns for both phases contain a number of broad, weak superlattice peaks attributed to ordering of the Ba2+ ions within the tunnels of the hollandite framework structure. According to the criteria developed by Cheary and Squadrito [Acta Crystallogr. B 45, 205 (1989)], the observed positions of the (0k1)/(1k0) superlattice peaks are consistent with the nominal x-values of both compounds, and the k values calculated from the corresponding d-spacings suggest that the Ba ordering within the tunnels is commensurate for x=1.333 and incommensurate for x=1.143. High-temperature X-ray diffraction data indicate that the x=1.333 compound undergoes a monoclinic→tetragonal phase transition between 310 and 360 °C.

The phase transition IV/II of ammonium nitrate investigated by X-ray diffraction

1983 ◽  
Vol 164 (3-4) ◽  
Author(s):  
W. Engel ◽  
N. Eisenreich
Keyword(s):  
Phase Transition ◽  
Ammonium Nitrate ◽  
Temperature Interval ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Diffraction Patterns ◽  
Phase Iv

AbstractSeries of diffraction patterns were measured with dry powdered ammonium nitrate from 50 – 60°C on heating and from 50 – 40°C on cooling. The variation of lattice constants allows to observe the transition. On heating the phase transition IV/II occurs between 52 and 56°C. In this temperature interval both phases are existent. On cooling, simultaneous transitions II/IV and II/V occur with phase V slowly transforming into phase IV.

scholarly journals Studies of phase transition and impedance behavior of Ba(Zr, Ti)O3 ceramics

2015 ◽  
Vol 05 (01) ◽  
pp. 1550002 ◽  
Author(s):  
P. Sateesh ◽  
J. Omprakash ◽  
G. S. Kumar ◽  
G. Prasad
Keyword(s):  
Phase Transition ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Phase Transition Behavior ◽  
Temperature Dependent ◽  
Conventional Solid State Reaction ◽  
Xrd Pattern ◽  
X Ray ◽  
Ceramic Samples ◽  
Barium Zirconium Titanate

Ceramic samples of Barium Zirconium Titanate ( BaZr x Ti 1-x O 3 ( BZT )) were synthesized by conventional solid-state reaction method with different concentrations of x(= 0.05 ( BZT1 ), 0.10 (BZT2), 0.15 (BZT3), 0.20 (BZT4), 0.25 (BZT5), 0.30 (BZT6)). Phase confirmation of the samples was done by X-ray diffraction (XRD) technique. All the compositions are in cubic structure. XRD pattern was recorded for samples sintered at different sintering temperatures. Lattice parameters increased with addition of Zr +4. Doping with Zr +4 into Barium titanate resulted in interesting changes of electrical properties (dielectric, impedance and ferroelectiricity). The strong influence of Zr doping on the phase transition characteristics of the BZT ceramics was studied from the dielectric response of the samples. Diffusivity of phase transition of the BZT ceramic samples increase with Zr +4 concentration, indicating changes from normal to diffuse transition to relaxor phase transition behavior. Impedance spectroscopy reveals the presence of temperature-dependent grain, grain boundary effects. Polarization–Electricfield (PE) loop measurements are also done on the samples.

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