POTASSIUM-SODIUM-RUBIDIUM NIOBATE SINGLE CRYSTALS AND ELECTRIC PROPERTIES

2009 ◽  
Vol 23 (17) ◽  
pp. 3631-3636 ◽  
Author(s):  
H. KIMURA ◽  
R. TANAHASHI ◽  
K. MAIWA ◽  
H. BABA ◽  
Z. X. CHENG ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Single Crystals ◽  
Room Temperature ◽  
Single Phase ◽  
Electric Properties ◽  
Potassium Niobate ◽  
Composition Change ◽  
Potassium Sodium ◽  
Co Doping ◽  
Ionic Size

Potassium-sodium-rubidium niobate single crystals are grown using an original pulling down method, to improve their composition change during a crystal growth, by means of co-doping of small ionic size sodium and large ionic size rubidium into potassium niobate. Even by the co-doping, single crystals can be grown with orthorhombic single-phase at room temperature, as well as pure potassium niobate. Their electric properties, such as the dielectric constant and the impedance, are changed depending on the doping ions.

Introduction of Fine Engineered Domain Configuration into Potassium Niobate Single Crystals

2007 ◽  
Vol 350 ◽  
pp. 89-92
Author(s):  
Keisuke Yokoh ◽  
Tomomitsu Muraishi ◽  
Song Min Nam ◽  
Hirofumi Kakemoto ◽  
Takaaki Tsurumi ◽  
...  
Keyword(s):  
Electric Field ◽  
Single Crystals ◽  
Room Temperature ◽  
Single Domain ◽  
Potassium Niobate ◽  
Field Exposure ◽  
Domain State ◽  
Domain Configuration ◽  
Dc Electric Field ◽  
Direction Of Polarization

To induce fine engineered domain configurations into potassium niobate (KNbO3) single crystals, two kinds of methods were performed, i.e., (1) high DC electric field exposure along the opposite direction of polarization of KNbO3 single-domain crystals at room temperature, and (2) introduction of randomly oriented fine domain configuration by heat treatment at 700 °C and then high DC electric field exposure along [001]c direction of KNbO3 multidomain crystals at room temperature. When the method (1) was performed, finally, the poled KNbO3 crystals became to single-domain state again through the formation of multidomain state. On the other hand, the KNbO3 multidomain crystals were obtained by using the method (2), and an enhancement of piezoelectric-related properties was observed.

scholarly journals Structure and electric properties of cerium substituted SrBi1.8Ce0.2Nb2O9 and SrBi1.8Ce0.2Ta2O9 ceramics

2016 ◽  
Vol 10 (3) ◽  
pp. 183-188 ◽  
Author(s):  
Mohamed Afqir ◽  
Amina Tachafine ◽  
Didier Fasquelle ◽  
Mohamed Elaatmani ◽  
Jean-Claude Carru ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Room Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Lcr Meter ◽  
Curie Temperature Tc

SrBi1.8Ce0.2Nb2O9 (SBCN) and SrBi1.8Ce0.2Ta2O9 (SBCT) powders were prepared via solid-state reaction method. X-ray diffraction analysis reveals that the SBCN and SBCT powders have the single phase orthorhom-bic Aurivillius structure at room temperature. The contribution of Raman scattering and FTIR spectroscopy of these samples were relatively smooth and resemble each other. The calcined powders were uniaxially pressed and sintered at 1250?C for 8 h to obtaine dense ceramics. Dielectric constant, loss tangent and AC conductivity of the sintered Ce-doped SrBi2Nb2O9 and SrBi2Ta2O9 ceramics were measured by LCR meter. The Ce-doped SBN (SBCN) ceramics have a higher Curie temperature (TC) and dielectric constant at TC (380?C and ?? ~3510) compared to the Ce-doped SBT (SBCT) ceramics (330?C and ?? ~115) when measured at 100Hz. However, the Ce-doped SBT (SBCT) ceramics have lower conductivity and dielectric loss.

Phase Formation and Grain Growth of BSCZT Ceramics Prepared by BST-BZT Seed Induced Method

2018 ◽  
Vol 766 ◽  
pp. 175-179
Author(s):  
Jiraporn Dangsak ◽  
Sukum Eitssayeam ◽  
Denis Russell Sweatman ◽  
Uraiwan Intatha
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Phase Formation ◽  
Room Temperature ◽  
Single Phase ◽  
Seed Crystal ◽  
Lead Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Density Values

In this work, lead-free Ba0.4Sr0.4Ca0.2Zr0.05Ti0.95O3 ceramics were prepared by the seed induced method using (0.5Ba0.6Sr0.4TiO3–0.5BaZr0.05Ti0.95O3) (BST-BZT) seed. Seed crystals with concentrations of 0, 2.5, 5, 7.5, 10 mol% were mixed with BSCZT powder for 24 h and sintered at 1400 °C for 4 h. The phase formation and microstructure of BSCZT ceramic were characterized by X-ray diffraction technique (XRD) and the scanning electron microscopy (SEM). All samples showed a single phase perovskite structure without impurities and exhibited the existence of the tetragonal phase. The density values of the ceramics decreased from 4.90 to 4.75 g/cm3 with increasing seed crystal concentrations. The grain size of the sample without seed was 3.71 μm, whereas a grain size of 8.99 μm was observed for the sample with 10 mol% seed crystal. The dielectric constant at room temperature at 1 kHz was 1831 for the sample with 10 mol% seed crystal while the dielectric constant of the sample without seed was 1484. From the results in this work, BST-BZT seed can increase grain size and improve the dielectric constant at room temperature.

DIELECTRIC STUDIES OF SAMARIUM MODIFIED (Pb)(Zr, Ti, Fe, Nb)O3 CERAMIC SYSTEM

2009 ◽  
Vol 23 (11) ◽  
pp. 1437-1442 ◽  
Author(s):  
PRATIBHA SINGH ◽  
SANGEETA SINGH ◽  
J. K. JUNEJA ◽  
CHANDRA PRAKASH ◽  
K. K. RAINA
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
Single Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Dielectric Studies ◽  
Dielectric Measurements ◽  
Ceramic System ◽  
Reaction Method ◽  
Room Temperature Dielectric Constant

Here we report the investigations on Sm -substituted PZTFN ( Pb 1-x Sm x Zr 0.588 Ti 0.392 Fe 0.01 Nb 0.01 O 3) (where x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) polycrystalline solid solutions fabricated by solid-state reaction method. XRD analysis shows all the samples to be single phase with tetragonal structure. Dielectric measurements were carried out in the temperature range 30°C–400°C at different frequencies in the range 100 Hz to 100 kHz. From the temperature variation of dielectric constant (ε), Curie temperature (TC) was determined which was found to decrease with increasing x. The room temperature dielectric constant (ε RT ) initially increases with increasing x and then starts decreasing. Dielectric loss improves with Sm -doping.

Dielectric properties of normal, reduced, and specially reduced rutile (TiO2) single crystals at room temperature

1969 ◽  
Vol 47 (1) ◽  
pp. 3-6 ◽  
Author(s):  
H. B. Lal ◽  
K. G. Srivastava
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Oxygen Vacancy ◽  
Single Crystals ◽  
Room Temperature ◽  
Interfacial Polarization ◽  
Absorption Peak ◽  
Single Relaxation Time

The variation of the dielectric constant (ε′) and the dielectric loss (ε″) have been studied as a function of frequency (102 to 1010 c.p.s.) for normal (as grown), reduced (heated in vacuum), and specially reduced (heated in vacuum in presence of an asymmetric d.c. field) rutile single crystals parallel to c-axis at room temperature. Dispersions in ε′ have been observed in the frequency ranges 102 to 103 and 107 to 109 c.p.s. for all the samples with absorption peaks in ε″ at 2 × 102 and 6 × 107 c.p.s. Also an extra absorption peak in ε″ has been found at 2 × 104 c.p.s. for the specially reduced sample. The absorption peak at 2 × 102 c.p.s. has been observed by many workers and is typical for interfacial polarization. The peak at 6 × 107 c.p.s. appears to be due to a dipole rotation process with a single relaxation time and is identified as due to relaxation of dipoles formed between Ti3+ and a neighboring oxygen vacancy. The possible mechanism of relaxation for the 2 × 104 c.p.s. absorption peak is also discussed.

Preparation of Potassium Niobate-Coated Barium Titanate Accumulation Ceramics by Solvothermal Synthesis and Enhancement of Piezoelectric Property

2013 ◽  
Vol 566 ◽  
pp. 76-80 ◽  
Author(s):  
Kenta Yamashita ◽  
Shigehito Shimizu ◽  
Nobuhiro Kumada ◽  
Kouichi Nakashima ◽  
Ichiro Fujii ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Piezoelectric Property ◽  
Solvothermal Synthesis ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Solvothermal Method ◽  
Potassium Niobate ◽  
Nanostructured Ceramics ◽  
Dielectric And Piezoelectric Properties

Barium titanate (BaTiO3, BT) - potassium niobate (KNbO3, KN) nanostructured ceramics with artificial morphotropic phase boundary (MPB) structure were successfully prepared at temperatures below 230 °C by solvothermal method. Various characterizations suggested that the BT-KN nanostructured ceramics exhibited a porosity of around 30 % and heteroepitaxial interface between BT and KN. Their dielectric and piezoelectric properties were measured at room temperature, and the dielectric constant and apparent piezoelectric constant estimated from slope of strain and electric field curve was 370 and 136 pm/V, respectively.

Sintering, Microstructure and Electrical Properties of MnO2 and CuO-Doped [Na0.515K0.485]0.94Li0.06(Nb0.99Ta0.01)O3 Ceramics

2013 ◽  
Vol 770 ◽  
pp. 258-261
Author(s):  
Pornsuda Bomlai
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Room Temperature ◽  
Secondary Recrystallization ◽  
Lead Free ◽  
Reaction Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Sintering Method

Ceramics with formula (1-x-y)[Na0.515K0.485]0.94Li0.06(Nb0.99Ta0.01)O3 (NKLNT) xMnO2yCuO (when x, y = 0, 0.005 and 0.01) were prepared by a reaction sintering method. The effects of doping level on sinterability and properties of NKLNT ceramics were studied. The results indicated that the co-doping of MnO2 and CuO was effective in promoting the densification of ceramics. Grain growth during secondary recrystallization was also affected, leading to larger grain size with x, y = 0.01 sample. X-ray diffraction data showed that the orthorhombic tetragonal morphotropic phase boundary existed in all the samples. At room temperature, the dielectric properties of NKLNT ceramics were improved by doping of appropriate MnO2 and CuO content. The temperature dependence of dielectric constant showed a decrease slightly in Curie temperature (TC) with increasing MnO2 and CuO content. The composition with x = 0.005, y = 0 exhibited favorable properties for the promising lead-free piezoelectric candidate material.

Effect of Different Doping on the Structure and Field-Stability of PMNT Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 36-38
Author(s):  
Xiao Wei Wen ◽  
Chu De Feng ◽  
Li Dong Chen ◽  
Shi Ming Huang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Perovskite Structure ◽  
Single Phase ◽  
Secondary Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Diffraction Patterns

Effect of co-doping two different elements and incorporating SrBi2Nb2O9 (SBN) on structure and field-stability of dielectric properties in PMNT ceramics were investigated. Single-phase cubic Perovskite structure is more easily obtained by appropriate co- doping of La3+ and Zn2+. X-ray diffraction patterns of PMNT/SBN composite showed that there is no SBN grains in PMNT/SBN as a secondary phase. Co-doping of La3+ and Zn2+ as well as incorporation of SBN markedly increased the field-stability of dielectric constant. The mechanism of improving field-stability was tentatively discussed.

Domain Wall Engineering in Potassium Niobate Single Crystals and Their Piezoelectric Properties

2006 ◽  
Vol 320 ◽  
pp. 147-150
Author(s):  
Keisuke Yokoh ◽  
Song Min Nam ◽  
Hirofumi Kakemoto ◽  
Takaaki Tsurumi ◽  
Hirohiko Kumagai ◽  
...  
Keyword(s):  
Phase Transition ◽  
Domain Wall ◽  
Electric Field ◽  
Single Crystals ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Potassium Niobate ◽  
Wall Region ◽  
Domain Configuration ◽  
Piezoelectric Constants

For potassium niobate (KNbO3) single crystal, the 31 resonators with the highest piezoelectric constant d31 were designed using transformation of axis. We confirmed that the engineered domain configurations with maximum d31 of –55.1 pC/N was caused by a combination between two polarization with polar directions along [101]c and [-101]c directions. Moreover, if there are larger piezoelectric constants from domain wall region, we can expect the much higher piezoelectric properties. To induce the above domain configuration, a new poling method using patterning electrode was investigated. In this study, the two methods on the basis of temperature-induced phase transition at 207 °C and electric-field-induced phase transition at room temperature were investigated.

Elastic properties of tetragonal PbTiO3 single crystals by Brillouin scattering

1997 ◽  
Vol 12 (10) ◽  
pp. 2623-2627 ◽  
Author(s):  
A. G. Kalinichev ◽  
J. D. Bass ◽  
B. N. Sun ◽  
D. A. Payne
Keyword(s):  
Dielectric Constant ◽  
Light Scattering ◽  
Acoustic Wave ◽  
Single Crystals ◽  
Elastic Properties ◽  
Room Temperature ◽  
Brillouin Scattering ◽  
Wave Velocities ◽  
Transverse Acoustic ◽  
Piezoelectric Constants

Brillouin light scattering was used to obtain the elastic and piezoelectric constants for tetragonal PbTiO3 single crystals at room temperature. Approximately 170 measurements of longitudinal and transverse acoustic wave velocities were inverted using literature dielectric constant values to obtain the full set of elastic and piezoelectric constants. Our data indicate a greater electromechanical anisotropy in the polar c direction than previously reported, but are otherwise in general agreement with previous studies. We discuss briefly the degree to which individual elastic and piezoelectric constants are resolved.

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