The Microstructure and Dielectric Properties of SrTiO3 Modified 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 Ceramics

2011 ◽  
Vol 687 ◽  
pp. 433-438
Author(s):  
Jing Song Liu ◽  
Tao Li ◽  
Hui Qin Li ◽  
You Chao Xu ◽  
Ji Qiang Yu
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Spontaneous Polarization ◽  
Relaxor Behavior ◽  
Maximum Dielectric Constant ◽  
Lower Temperature ◽  
Region Size ◽  
Maximum Permittivity

The microstructure and dielectric properties of ferroelectric solutions which is formulated with (1-x)[0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3]-x mol% SrTiO3(x=0, 1, 3 and 5) have been investigated. The ceramics was fabricated by a modified columbite route sintered at 1200 °C. The effects of dopants on microstructure, maximum dielectric constant (εm) and diffuseness of the phase transition, etc. have been studied. It is found that the maximum permittivity (εm) increases to 24968 for the ST-doped (1 mol %) sample, subsequently decreases with ST addition and its corresponding phase-transition-temperature (Tm) shifts to the lower temperature. The variation of εmis caused by the decrease of polar nano-region size, increase of the fluctuation of the component and the increase of the effective spontaneous polarization. The enhancement of relaxor behavior in the PMN-PT sample is explained by the decrease of FE/AFE coupling.

STUDIES ON ORIENTED DOMAIN POLYSTYRENE-TGS COMPOSITE FILMS

1995 ◽  
Vol 09 (17) ◽  
pp. 1039-1044
Author(s):  
S.C. MATHUR ◽  
D.S. RAWAT ◽  
H.O. YADAV ◽  
D.C. DUBE ◽  
A.S. BHALLA
Keyword(s):  
Dielectric Constant ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Domain Structure ◽  
Spontaneous Polarization ◽  
Coercive Field ◽  
Composite Films ◽  
Microwave Frequency ◽  
Ferroelectric Films ◽  
Microwave Frequencies

Polymer ferroelectric films were prepared by dispersing TGS powder in polystyrene. Permittivity versus temperature plots exhibit a peak at around the transition temperature of TGS. The peak gets suppressed with increasing frequency and the trend continues up to microwave frequencies. We observed that the dielectric constant of films at microwave frequency stays close to the dielectric constant of polystyrene. The domain structure of TGS crystals essentially seems to affect their dielectric properties. Single domain films exhibit a higher spontaneous polarization and a higher coercive field.

Dielectric Properties of 0.9PMNTa-0.1PT Relaxor

2000 ◽  
Author(s):  
Feng Tang ◽  
Jin T. Wang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Test Chamber ◽  
Frequency Dispersion ◽  
Relaxor Behavior ◽  
Lead Magnesium ◽  
Constant Versus ◽  
Lower Temperature ◽  
Ta Doping

Abstract Ta-Modified lead magnesium niobate-lead titanate crystalline solutions 0.9PbMg1/3(Nb(1−x)Tax)2/3O3-0.1PbTiO3 (PMN-PT) were first synthesized. The dielectric constant and the dielectric loss of the ceramic for different compositions as a function of frequency and temperature were measured using a Hewlett Packard 4284A LCR precision meter, which can cover a frequency range from 20 to 106Hz in a Delta 9039 test chamber operated between −75°C to +330°C. Dramatic changes of the dielectric properties were observed in Ta-modified 0.9PMN-0.1PT. It was noticed that the samples with appropriate amount of Ta-doping (x = 0.1, 0.2, and 0.3) have smaller grain size, larger dielectric constant, and lower dielectric loss than those of the specimens without doping (x = 0.0) or over doping (x = 1.0) in the frequency band of 100 – 105Hz. Proper Ta-doping in PMN-PT also resulted in a weaker frequency dispersion. It was also found that with increasing of Ta addition x, the transition temperature shifts downward to the lower temperature and the peaks of the dielectric constant versus temperature are getting sharper. Ta-doped PMNTa-PT shows a typical relaxor behavior.

Sintered compacts of nano and micron-sized BaTiO3: Dramatic influence on the microstructure and dielectric properties

2006 ◽  
Vol 21 (4) ◽  
pp. 816-822 ◽  
Author(s):  
Vishnu Shanker ◽  
Tokeer Ahmad ◽  
Henry Ip ◽  
Ashok K. Ganguli
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
High Dielectric Constant ◽  
Scanning Calorimetry ◽  
Ferroelectric Transition ◽  
Maximum Dielectric Constant ◽  
High Dielectric ◽  
First Time

Sintered compacts of nano-sized and micron-sized BaTiO3 show sharp ferroelectric transition and high dielectric constant at specific compositions. The sintered compacts with 1 wt% nano-BaTiO3 show a maximum dielectric constant of 1680. At the transition temperature (Tc) there are two maxima at 0.5 and 2 wt%. The variation in the dielectric constant at Tc is also reflected in the behavior of the ferroelectric transition as studied by differential scanning calorimetry. This interesting oscillatory variation of the dielectric constant and dielectric loss with increase in the amount of nanoparticles in the sintered compacts is observed for the first time. The variation of the dielectric properties and the ferroelectric transition of the sintered compacts could be related to subtle changes in the microstructure.

The Effect of Zn2+ Deficiency on Ordered Micro-Regions and Dielectric Properties of Pb(Zn1/3Nb2/3)O3-Based Relaxor Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 27-29
Author(s):  
Shao Bo Qu ◽  
Bin Ke Wang ◽  
Zhi Yi Liu ◽  
Zhi Bin Pei ◽  
Zhuo Xu
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Ternary System ◽  
Raman Scattering ◽  
Phase Structure ◽  
Close Correlation ◽  
Scattering Spectra ◽  
Raman Scattering Spectra ◽  
Region Size

0.85Pb(Zn1/3Nb2/3)O3-0.10BaTiO3-0.05PbTiO3 (abbreviated as PZN-based ceramics hereafter) ternary system ceramics with Zn2+ deficiency were synthesized by the columbite method. The effect of deficient Zn2+ on phase structure, ordered micro-region size and dielectric properties was investigated in detail. The analysis of Raman scattering spectra demonstrated that Zn2+ deficiency sharply enlarged the ordered micro-region size. Zn2+ deficiency significantly increased the dielectric constant, and decreased the diffusion degree of phase transition. There is a close correlation between effective ordered micro-regions size and dielectric properties for the PZN-based ceramics.

Effects of thermal annealing on the dielectric properties of Pb(Zn1/3Nb2/3)O3-based ceramics

1999 ◽  
Vol 14 (5) ◽  
pp. 1683-1685 ◽  
Author(s):  
Feng Xia ◽  
Xi Yao
Keyword(s):  
Dielectric Constant ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Thermal Annealing ◽  
Wall Motion ◽  
Relative Dielectric Constant ◽  
Domain Wall Motion ◽  
Dissipation Factor ◽  
Diffusion Factor ◽  
Maximum Dielectric Constant

Pb(Zn1/3Nb2/3)O3-based ceramics were thermally annealed at 700–900 °C for 4 h. Both the relative dielectric constant and dissipation factor in the vicinity of transition temperature were increased when the specimens were thermally annealed at 700–900 °C, but the diffusion factor was decreased. After thermal annealing, the maximum dielectric constant Km was increased from about 11,000 to 26,000. These phenomena can be related to the domain wall motion and the elimination of internal stress.

scholarly journals Phase transition and dielectric properties of BaTiO3 ceramics containing 10 mol% BaGeO3

2018 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Phase Transition Temperature ◽  
Ferroelectric Phase ◽  
Grain Sizes ◽  
Ferroelectric Phase Transition Temperature ◽  
Permittivity Maximum ◽  
Tetragonal Phase Transition ◽  
Maximum Permittivity

Dielectric properties and the cubic ? tetragonal phase transition temperature ofdense BaTiO3 ceramics containing 10 mol% BaGeO3, sintered between 840 and 1350 °C,have been investigated. The ceramic bodies were prepared from a nano-sized BaTi0.9/Ge0.1O3powder consisting of both BaTiO3 and BaGeO3 phases. The addition of BaGeO3 leads to areduction and broadening of the permittivity maximum, and to a small downshift of theparaelectric ? ferroelectric phase transition temperature, compared to a pure BaTiO3 ceramic.Lower sintering temperatures and thus small grain sizes of the ceramics cause an additionalreduction of the maximum permittivity down to 2800. Both DTA and dilatometricmeasurements reveal also a downshifting of the phase transition temperature, as well as adecrease of the latent heat.

scholarly journals Размерный эффект в нанокомпозитах на основе молекулярного сегнетоэлектрика бромида диизопропиламмония

2019 ◽  
Vol 61 (2) ◽  
pp. 273
Author(s):  
C.B. Барышников ◽  
А.Ю. Милинский ◽  
E.B. Чарная ◽  
И.В. Егорова
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Size Effects ◽  
Low Temperatures ◽  
Structural Phase ◽  
Theoretical Models ◽  
Temperature Hysteresis ◽  
And Diffusion

AbstractWe present the results of studies of the dielectric properties of nanocomposites based on Al_2O_3 oxide films with a pore size of 330 and 60 nm with particles of an organic ferroelectric diisopropylammonium bromide (C_6H_16BrN, DIPAB) introduced into the pores, aimed at determining the size dependences of phase transition parameters. A shift in the phase transition to low temperatures and diffusion of the transition are found, which become more significant for smaller pores. A broadening of the temperature hysteresis of the dielectric constant of nanocomposites during the phase transition was also observed. The decrease in the phase transition temperature in nanocomposites with DIPAB nanoparticles is consistent with theoretical models of the size effects on the structural phase transition.

Change of Phase Transition Temperature in Band Engineered Ferroelectric Lanthanum-Modified Bismuth Titanates

2020 ◽  
Vol 20 (11) ◽  
pp. 7135-7139
Author(s):  
Rui Tang ◽  
Sangmo Kim ◽  
Chung Wung Bark
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Ferroelectric Properties ◽  
Solar Spectrum ◽  
Ferroelectric Material ◽  
Transition Temperatures ◽  
Phase Transition Temperatures ◽  
Increasing Temperature

The ferroelectric material chosen for a solar cell has to absorb as much of the solar spectrum as possible, therefore a low band gap is desirable, but it is rarely known for phase transition temperature on the bandgap engineered ferroelectric materials. The phase transition temperature of a ferroelectric material can be determined by monitoring its dielectric constant with increasing temperature, as the dielectric constant changes abruptly at the phase transition temperature. Here, we inform the measurement of the phase transition temperature of the ferroelectric complex oxide Bi3.25La0.75Ti3O12 as well as cobalt and iron doped Bi3.25La0.75Ti3O12 bulk ceramics for photovoltaic cells based on dielectric monitoring with changing temperature. We synthesized lanthanum-modified bismuth-titanate-based ceramics with various doping concentrations transition metal to Ti. X-ray diffraction analysis revealed that all the compounds crystallized in an orthorhombic structure. Their morphologies and size distributions were observed using scanning electron microscopy. From the ultraviolet-visible spectroscopy absorption spectra of the synthesized powder, bandgaps were checked. An inductance-capacitance-resistance meter was used to obtain the relationship between dielectric responses and the temperature of the targets in a tube furnace. We observed that the dielectric constant increases gradually with increasing temperature, until the transition temperature and subsequently decreases, and we were able to determine the phase transition temperatures of the tested materials. Furthermore, the results revealed that all the doped bismuth titanates keep their phase transition temperatures, which were sufficiently high, to maintain their ferroelectric properties above room temperature.

Diffuse Phase Transition and Dielectric Properties of Lead-Free Zr-Doped BCTS Ceramics

2017 ◽  
Vol 866 ◽  
pp. 259-262 ◽  
Author(s):  
Puripat Kantha ◽  
Kamonpan Pengpat ◽  
Nuttapon Pisitpipathsin
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Diffuse Phase Transition ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Phase Transition Behavior ◽  
Conventional Solid State Reaction ◽  
Maximum Dielectric Constant ◽  
Cubic Structure ◽  
Diffuse Phase

Lead-free Ba0.9Ca0.1Sn0.06Ti0.94-xZrxO3 (BCTSZ) ceramics where x = 0.00, 0.03, 0.05, 0.07 and 0.09 were prepared by the conventional solid-state reaction method. The dielectric constant of the Zr doped BCTS ceramic was enhanced by Zr incorporation. The maximum dielectric constant were obtained at the composition of x = 0.05. The dielectric property investigation indicated that the degree of the diffuse phase transition behavior increased with Zr substitution. Phase transition of tetragonal to cubic structure was significantly dependent on the amount of Zr added.

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