Enhanced Tunability Properties of Pure (Ba,Sr)TiO3 Lead free Ferroelectric by Polar Nano-region Contributions

2021 ◽  
Author(s):  
Abdelrazek Mahmoud ◽  
Samar Moen ◽  
M.K. Gerges
Keyword(s):  
Electric Fields ◽  
Room Temperature ◽  
Single Phase ◽  
Domain Switching ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Lead Free ◽  
Multiple Components ◽  
The Difference ◽  
Lower Temperature

Abstract In the present work, a series compositions of (Ba1-xSrx)TiO3 (0≤x≤0.4) lead-free ferroelectric (BST) were successfully prepared by sol-gel method. The effects of Sr2+ on the optical properties, crystal structure and morphology of BaTiO3 were systematically investigated. Compositions with x<0.4 exhibit single phase tetragonal perovskite at room temperature, while a cubic structure of BST has been detected in the ceramic with x=0.4. Phase transition temperature was shifted toward lower temperature by increasing Sr-doping. Moreover, detailed tunability analysis for the present ceramics confirmed an enhancement by Sr-addition and the maximum values were observed at Sr=0.2. The enhancement back to present multiple components contribute to the dc-field induced dielectric constant, where at low electric fields the Langevin theory indicate present polar nano-region (PNR) contributions into tunability data, however domain switching contributions at high electric field was described by Johnson equation. Ferroelectric properties appraised by P-E loop and positive up negative down (PUND) methods have been introduced. The results shown the remnant polarization appraised by PUND method is much lower than polarization estimated by P-E loop indicate the difference values of Pr is mostly owing to leakage current contribution in P-E method.

Synthesis and Properties of Lead Free Ferroelectric Na0.5Bi0.5TiO3 Ceramic at Different Sintering Temperature

2015 ◽  
Vol 830-831 ◽  
pp. 620-623 ◽  
Author(s):  
Kusum Parmar ◽  
Hakikat Sharma ◽  
Sarita Sharma ◽  
N.S. Negi
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Lead Free ◽  
Characteristic Absorption Band ◽  
Different Temperatures ◽  
Xrd Patterns ◽  
Rhombohedral Symmetry

Lead Free Ferroelectric Na0.5Bi0.5TiO3 (NBT) Ceramic has been synthesized using sol gel method. The prepared NBT samples have been sintered at different temperatures 850°C, 950°C, 1050°C and 1150°C to achieve best sintering temperature. Structural analyses have been carried out using XRD and FTIR measurements. XRD patterns confirm perovskite structure having rhombohedral symmetry for all samples which is also supported by characteristic absorption band at ~627cm-1 in FTIR spectra. Dielectric properties of NBT samples with frequency and temperature have been studied. NBT sample sintered at 1050°C exhibit comparatively high value of dielectric constant (ε’) and phase transition temperature (Tm). Ferroelectric properties of NBT samples have been studied at room temperature. Comparatively, better ferroelectric properties are observed for NBT sample having remnant polarization (Pr)~ 14.7 μC/cm2and coercive field (Ec)~ 26.8 kV/cm sintered at 1050°C.

Impedance Spectroscopy Study of LiTaO3 Powder Synthesized via Sol-Gel Method

2012 ◽  
Vol 545 ◽  
pp. 275-278 ◽  
Author(s):  
Lili Widarti Zainuddin ◽  
Norlida Kamarulzaman
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Sol Gel ◽  
Rhombohedral Structure ◽  
Spectroscopy Study ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Impedance Spectroscopy Study

A ceramics sample of LiTaO3 was prepared using a sol-gel method. The sample is annealed at 750 °C for 48 hours. X-ray diffraction analysis indicate the formation of single phase, rhombohedral structure. An ac impedance study was used to analyse the conductivity of LiTaO3 at room temperature and at various temperatures.

Influence of Excess Potassium on Structural and Ferroelectric Properties of Lead-Free Bi0.5K0.5TiO3 Thin Films

2021 ◽  
Vol 21 (4) ◽  
pp. 2681-2686
Author(s):  
Nguyen Ngoc Minh ◽  
Bui Van Dan ◽  
Nguyen Duc Minh ◽  
Guus Rijnders ◽  
Ngo Duc Quan
Keyword(s):  
Thin Films ◽  
Chemical Solution Deposition ◽  
Single Phase ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Chemical Solution ◽  
Ferroelectric Films ◽  
Solution Deposition ◽  
Si Substrates ◽  
Excess Amount

Lead-free Bi0.5K0.5TiO3 (BKT) ferroelectric films were synthesized on Pt/Ti/SiO2/Si substrates via the chemical solution deposition. The influence of the excess potassium on the microstructures and the ferroelectric properties of the films was investigated in detail. The results showed that the BKT films have reached the well-crystallized state in the single-phase perovskite structure with 20 mol.% excess amount of potassium. For this film, the ferroelectric properties of the films were significantly enhanced. The remnant polarization (Pr) and maximum polarization (Pm) reached the highest values of 9.4 μC/cm2 and 32.2 μC/cm2, respectively, under the electric field of 400 kV/cm.

Structural, Electrical and Magnetic Properties of Modified Bi1/2Na1/2TiO3 - Modified CFO Based Magnetostrictive (Co0.6Zn0.4Fe1.7Mn0.3O4) Particulate Nanocomposite

2017 ◽  
Vol 886 ◽  
pp. 13-16
Author(s):  
Mintu Tyagi ◽  
Vinod Kumar ◽  
Gurpreet Kaur ◽  
Puneet Sharma
Keyword(s):  
Magnetic Properties ◽  
Magnetic Measurements ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Lead Free ◽  
Great Opportunity ◽  
Electrical And Magnetic Properties ◽  
Device Applications ◽  
Two Phases

Lead free Multiferroic composites that comprise Co0.6Zn0.4Fe1.7Mn0.3O4 (CZFMO) and 72.5(Bi1/2Na1/2TiO3)-22.5(Bi1/2K1/2TiO3)-5(BiMg1/2Ti1/2O3) (BNT-BNT-BMgT) were synthesized using sol-gel method and it’s structural, ferroelectric and magnetic properties were studied. The X-ray diffraction displayed the single phase formation of parent phases and the presence of two phases in the composites. The samples showed a well saturated polarization-electric field hysteresis loops. The remnant polarization and saturation polarization values are decreased with increasing ferrite content. Room temperature (RT) magnetic measurements show that composites are soft magnetic. The composite with x = 0.2, showed the enhanced magnetic and ferroelectric properties. Moreover, these ME composites provide a great opportunity as potential lead free systems for multifuntional device applications.

Effect of sol–gel synthesis method on the structural, electrical, and ferroelectric properties of lead-free K0.5Na0.5NbO3 ceramic

2019 ◽  
Vol 92 (1) ◽  
pp. 215-223 ◽  
Author(s):  
Shammi Kumar ◽  
Mamta Shandilya ◽  
Shweta Thakur ◽  
Nagesh Thakur ◽  
Gun Anit Kaur
Keyword(s):  
Ferroelectric Properties ◽  
Sol Gel ◽  
Synthesis Method ◽  
Lead Free ◽  
Sol Gel Synthesis

scholarly journals Synthesis and characterization of lead-free ternary component BST–BCT–BZT ceramic capacitors

2014 ◽  
Vol 04 (02) ◽  
pp. 1450014 ◽  
Author(s):  
Venkata Sreenivas Puli ◽  
Dhiren K. Pradhan ◽  
Brian C. Riggs ◽  
Shiva Adireddy ◽  
Ram S. Katiyar ◽  
...  
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Energy Density ◽  
Electric Field ◽  
Hysteresis Loop ◽  
Electric Fields ◽  
Room Temperature ◽  
Thermal Hysteresis ◽  
Lead Free ◽  
Maximum Electric Field

Polycrystalline sample of lead-free 1/3( Ba 0.70 Sr 0.30 TiO 3) + 1/3( Ba 0.70 Ca 0.30 TiO 3) + 1/3( BaZr 0.20 Ti 0.80 O 3)( BST - BCT - BZT ) ceramic was synthesized by solid state reaction method. Phase purity and crystal structure of as-synthesized materials was confirmed by X-ray diffraction (XRD). Temperature-dependent dielectric permittivity studies demonstrated frequency-independent behavior, indicating that the studied sample has typical diffuse phase transition behavior with partial thermal hysteresis. A ferroelectric phase transition between cubic and tetragonal phase was noticed near room temperature (~ 330 K). Bulk P–E hysteresis loop showed a saturation polarization of 20.4 μC/cm2 and a coercive field of ~ 12.78 kV/cm at a maximum electric field of ~ 115 kV/cm. High dielectric constant (ε ~ 5773), low dielectric loss (tan δ ~ 0.03) were recorded at room temperature. Discharge energy density of 0.44 J/cm3 and charge energy density of 1.40 J/cm3 were calculated from nonlinear ferroelectric hysteresis loop at maximum electric field. Dielectric constant at variable temperatures and electric fields, ferroelectric to paraelectric phase transition and energy storage properties were thoroughly discussed.

The Preparation and Properties of (Na0.5+xK0.5-2xLix)NbO3 Lead-Free Piezoelectric Ceramics

2014 ◽  
Vol 602-603 ◽  
pp. 826-829
Author(s):  
Hong Yun Ma ◽  
Yan Gai Liu ◽  
Jin Qiu Zhao ◽  
Zhao Hui Huang ◽  
Ming Hao Fang
Keyword(s):  
Phase Composition ◽  
Piezoelectric Properties ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Piezoelectric Ceramics ◽  
Lead Free ◽  
Piezoelectric Constant ◽  
Pressureless Sintering ◽  
Gel Method ◽  
Sol Gel Method

In this paper, the KNN powders with Li+ substituted (K0.5Na0.5)+ were prepared by the sol-gel method in order to make powders pure, (Na0.50+xK0.50-2xLix) -NbO3 (x=0, 0.04, 0.06, 0.08) ceramics were prepared by pressureless sintering. The phase composition of powders was determined by XRD. The effects of the Li+ substitution on piezoelectric and ferroelectric properties of ceramics were systematically studied for determining optimal Li+ content. Li+ can significantly increase the piezoelectric constant of ceramic. When Li+ content was 0.04, piezoelectric properties of ceramics were the best, d33=115 pC/N, Pr=6.35 μC/cm2, Ec=14.24 kV/cm.

Piezoelectric and Ferroelectric Properties of KNbO3 Added Bi0.5Na0.5TiO3 Ceramics

2017 ◽  
Vol 751 ◽  
pp. 384-389 ◽  
Author(s):  
Puripat Kantha ◽  
Phathaitep Raksa ◽  
Muangjai Unruan ◽  
Tawee Tunkasiri ◽  
Panupong Jaiban ◽  
...  
Keyword(s):  
Mixed Oxide ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Piezoelectric Response ◽  
Rhombohedral Structure ◽  
Rhombohedral Symmetry

The fabrication of lead-free (1-x)Bi0.5Na0.5TiO3 - xKNbO3 or (1-x)BNT-xKN ceramics where x = 0.00, 0.05, 0.10, and 0.15 was carried out by the modified two-step mixed oxide method. The effects of KNbO3 on structure, piezoelectric and ferroelectric properties were systematically investigated. XRD results revealed that the (1-x)BNT-xKN ceramics with low KN content of x less than 0.05 contained ferroelectric phase with a rhombohedral symmetry while the ceramics with x = 0.05 possessed pseudocubic structure. The higher KN content (x ≥ 0.10) ceramics had symmetries rhombohedral structure. At room temperature, the highest Pr and low Ec were obtained when the composition of x = 0.05. Moreover, the results showed the moderate KN addition could enhance the piezoelectric response. The d33 of 0.95BNT-0.05KN reached as high as 125 pC/N.

Synthesis of Bismuth Ferrite and its Application for Oscillator Material up to 25 GHz Range

2021 ◽  
Vol 1028 ◽  
pp. 9-14
Author(s):  
Yeti Rafitasari ◽  
Ardita Septiani ◽  
Asep Ridwan Nugraha ◽  
Ervin Naufal Arrasyid ◽  
Dedi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Bismuth Ferrite ◽  
Sol Gel ◽  
Resonant Peak ◽  
Hysteresis Curve ◽  
Stoichiometric Ratio ◽  
Quenching Process ◽  
Potential Applications ◽  
Wide Potential

Among other multiferroic materials, bismuth ferrite (BiFeO3) attracts much attention due to its room-temperature properties and its wide potential applications. However, the synthesis to obtain a single-phase material is hard to be achieved because of the volatility of bismuth oxide. In this study, the BiFeO3 powders were synthesized by using a sol-gel method from the nitrates of bismuth and iron salt with the various stoichiometric ratios between Bi and Fe of 1:1.02, 1:1, 1.02:1, and 1.03:1. The single-phase and a good stoichiometric ratio of Bi: Fe = 1:1 was obtained from the starting composition ratio of 1.03:1 with a quenching process from 550°C sintering temperature. The single-phase of BiFeO3 shows a hysteresis curve of a weak antiferromagnetic with a coercive field of about 1.38 kOe at room temperature. The measurement of microwave oscillator was measured by using a dielectric resonator from 0 to 25 GHz does not show any resonant peak.

Synthesis and Ferroelectric Properties of Sr- and Nb-codoped Bi4−xSrxTi3−xNbxO12 Thin Films by Sol-Gel Method

2001 ◽  
Vol 688 ◽  
Author(s):  
Hirofumi Matsuda ◽  
Takashi Iijima ◽  
Hiroshi Uchida ◽  
Isao Okada ◽  
Takayuki Watanabe ◽  
...  
Keyword(s):  
Thin Films ◽  
Curie Temperature ◽  
Spin Coating ◽  
Single Phase ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Metal Alkoxide ◽  
Gel Method ◽  
Maximum Value ◽  
Chemical Solutions

AbstractFerroelectric Bi4Ti3O12 (BIT) thin films were modified by the substitution of Sr2+ ions for Bi3+ ions and of Nb5+ for Ti4+ (codoping) by spin-coating and decomposition of chemical solutions of metal-alkoxide materials (the nominal compositions of Bi4−xSrxTi3−xNbxO12 where x=0.0, 0.5, 1.0, 1.5). Single-phase thin films were crystallized above 550°C with BIT-type structure. The ferroelectric properties were found, though, with the values of Pr=10 μC/cm2 Ec=100 kV/cm, εr=300, and tanδ<5 % for Bi3.5Sr0.5Ti2.5Nb0.5O12 (x=0.5) annealed at 650 °C. Perhaps due to the lowering of the Curie temperature with increasing x, the maximum value of δr increased.

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