Texture – Property Relationships in Bi-Layered Ferroelectric Ceramics: A Case Study of SrBi2Ta2O9

2006 ◽  
Vol 514-516 ◽  
pp. 170-174 ◽  
Author(s):  
Harvey Amorín ◽  
Andréi L. Kholkin ◽  
Maria Elisabete V. Costa
Keyword(s):  
Spontaneous Polarization ◽  
Volume Fraction ◽  
Ferroelectric Properties ◽  
Hysteresis Loops ◽  
Orientation Distribution ◽  
Quantitative Model ◽  
Sem Analysis ◽  
Ferroelectric Ceramics ◽  
Sem Images ◽  
Predicted Values

A quantitative model for the calculation of spontaneous polarization of BLSF ceramics as a function of the degree of texture is presented using a general formalism based on the texture analysis via an orientation distribution function. The March-Dollase equation was selected to fit the measured texture distribution because its fitting parameters can be related to experimentally measurable stereological values obtained from SEM images. The results are applied to the SrBi2Ta2O9 (SBT) system, which is a well-known member of the BLSF family. The textured SBT ceramics were fabricated by templated grain growth (TGG) and the microstructure and degree of texture were evaluated by SEM analysis, which allowed correlating the texture development to the sintering parameters. Enhanced ferroelectric properties were measured perpendicularly to the uniaxial pressing direction of the ceramics, revealing the influence of the grains orientation, anisotropy and volume fraction of textured material on the ferroelectric properties. Finally, the predicted values for the spontaneous polarization as a function of the degree of texture were compared with those measured from the hysteresis loops.

A polycrystal hysteresis model for ferroelectric ceramics

2006 ◽  
Vol 462 (2069) ◽  
pp. 1573-1592 ◽  
Author(s):  
Y Su ◽  
G.J Weng
Keyword(s):  
Electric Field ◽  
Hysteresis Loop ◽  
Ferroelectric Properties ◽  
Electric Displacement ◽  
Hysteresis Loops ◽  
Ferroelectric Ceramics ◽  
Domain Growth ◽  
Thermodynamic Approach ◽  
Hysteresis Model ◽  
Self Consistent

Most key elements of ferroelectric properties are defined through the hysteresis loops. For a ferroelectric ceramic, its loop is contributed collectively by its constituent grains, each having its own hysteresis loop when the ceramic polycrystal is under a cyclic electric field. In this paper, we propose a polycrystal hysteresis model so that the hysteresis loop of a ceramic can be calculated from the loops of its constituent grains. In this model a micromechanics-based thermodynamic approach is developed to determine the hysteresis behaviour of the constituent grains, and a self-consistent scheme is introduced to translate these behaviours to the polycrystal level. This theory differs from the classical phenomenological ones in that it is a micromechanics-based thermodynamic approach and it can provide the evolution of new domain concentration among the constituent grains. It also differs from some recent micromechanics studies in its secant form of self-consistent formulation and in its application of irreversible thermodynamics to derive the kinetic equation of domain growth. To put this two-level micromechanics theory in perspective, it is applied to a ceramic PLZT 8/65/35, to calculate its hysteresis loop between the electric displacement and the electric field ( D versus E ), and the butterfly-shaped longitudinal strain versus the electric field relation ( ϵ versus E ). The calculated results are found to be in good quantitative agreement with the test data. The corresponding evolution of new domain concentration c 1 and the individual hysteresis loops of several selected grains—along with those of the overall polycrystal—are also illustrated.

Preparation and Ferroelectric Properties of Sol-Gel Derived (Ba0.95Ca0.05)TiO3 Ceramics

2011 ◽  
Vol 418-420 ◽  
pp. 362-367
Author(s):  
Xue Liang Yang ◽  
Xiang Yun Deng ◽  
Li Ren Han ◽  
Ren Bo Yang ◽  
Yan Jie Zhang ◽  
...  
Keyword(s):  
Ferroelectric Properties ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Structural Evolution ◽  
Ferroelectric Ceramics ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Scanning Calorimetry ◽  
Maximum Dielectric Constant ◽  
Sol Gel Process

Ba0.95Ca0.05)TiO3 (BCT) ferroelectric ceramics were prepared from powders synthesized using a sol–gel process. Structural evolution of the BCT dry gels are investigated by thermal gravimetric analysis differential scanning calorimetry. It is found that BCT crystallites can be formed before 800°C. Well-sintered samples are synthesized at 1320°C for 2h. The crystal structure of the BCT ceramics is studied by XRD and ferroelectric properties of the ceramics are characterized by TF analyzer 2000. The Curie temperature Tc of the BCT ceramics is at about 130°C. The maximum dielectric constant (εr) reaches about 13678 at 130°C and hysteresis loops are measured with the temperature range from 25°C to 150°C.

scholarly journals Dielectric and ferroelectric properties of CuO-doped lead magnesium niobate-based relaxor ferroelectric ceramics

2019 ◽  
Vol 09 (04) ◽  
pp. 1950033
Author(s):  
Li Jin ◽  
Jing Pang ◽  
Yunyao Huang ◽  
Wenting Luo ◽  
Xu Lu ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Pyrochlore Phase ◽  
Hysteresis Loops ◽  
Solid State Reaction Method ◽  
Relaxor Ferroelectric ◽  
Ferroelectric Ceramics ◽  
Conventional Solid State Reaction ◽  
Lead Magnesium ◽  
Relaxor Ferroelectric Ceramics

In this work, we report the dielectric and ferroelectric properties of CuO-doped ([Formula: see text])[0.5573Pb(Mg[Formula: see text]Nb[Formula: see text])O3-0.4427PbTiO3]-[Formula: see text]Ba(Zn[Formula: see text]Nb[Formula: see text]O3 (PMNT-[Formula: see text]BZN) relaxor ferrielectric ceramic samples with [Formula: see text], 0.1925, 02125 and 0.2325, which were fabricated by a conventional solid-state reaction method. By introducing the CuO into PMNT-[Formula: see text]BZN, the sintering temperature of this system is drastically lowered from 1280∘C to 1120∘C. The second pyrochlore phase, which is often generated during sintering at high temperature, is also inhibited. Meanwhile, broad dielectric peaks with strong dielectric relaxation characteristics are observed from [Formula: see text]C to 100∘C. Slim and slanted [Formula: see text]-[Formula: see text] hysteresis loops and purely electrostrictive strains with V-shape are obtained simultaneously in studied compositions from 30∘C to 150∘C. These results suggest that CuO could effectively lower the sintering temperature while maintaining the dielectric and ferroelectric properties of PMNT-[Formula: see text]BZN relaxor ferroelectric ceramics.

Influence of Multiwall Carbon Nanotube on mechanical and wear properties of Copper – Iron composite

2020 ◽  
Vol 17 (1) ◽  
pp. 7570-7576 ◽  
Author(s):  
H. Sh. Hammood ◽  
S. S. Irhayyim ◽  
A. Y. Awad ◽  
H. A. Abdulhadi
Keyword(s):  
Carbon Nanotubes ◽  
Volume Fraction ◽  
Hybrid Composites ◽  
Hydraulic Press ◽  
Dry Sliding Wear ◽  
Multiwall Carbon Nanotube ◽  
Wear Properties ◽  
Sem Images ◽  
Wear Rates ◽  
Multiwall Carbon

Multiwall Carbon nanotubes (MWCNTs) are frequently attractive due to their novel physical and chemical characteristics, as well as their larger aspect ratio and higher conductivity. Therefore, MWCNTs can allow tremendous possibilities for the improvement of the necessarily unique composite materials system. The present work deals with the fabrication of Cu-Fe/CNTs hybrid composites manufactured by powder metallurgy techniques. Copper powder with 10 vol. % of iron powder and different volume fractions of Multi-Wall Carbon Nanotubes (MWCNTs) were mixed to get hybrid composites. The hybrid composites were fabricated by adding 0.3, 0.6, 0.9, and 1.2 vol.% of MWCNTs to Cu- 10% Fe mixture using a mechanical mixer. The samples were compressed under a load of 700 MPa using a hydraulic press to compact the samples. Sintering was done at 900°C for 2 h at 5ºC/min heating rate. The microscopic structure was studied using a Scanning Electron Microscope (SEM). The effect of CNTs on the mechanical and wear properties, such as micro-hardness, dry sliding wear, density, and porosity were studied in detail. The wear tests were carried out at a fixed time of 20 minutes while the applied loads were varied (5, 10, 15, and 20 N). SEM images revealed that CNTs were uniformly distributed with relative agglomeration within the Cu/Fe matrix. The results showed that the hardness, density, and wear rates decreased while the percentage of porosity increased with increasing the CNT volume fraction. Furthermore, the wear rate for all the CNTs contents increased with the applied load.

scholarly journals Giant spontaneous polarization for enhanced ferroelectric properties of biaxially oriented poly(vinylidene fluoride) by mobile oriented amorphous fractions

2021 ◽  
Author(s):  
Guanchun Rui ◽  
Yanfei Huang ◽  
Xinyue Chen ◽  
Ruipeng Li ◽  
Dingrui Wang ◽  
...  
Keyword(s):  
Spontaneous Polarization ◽  
Vinylidene Fluoride ◽  
Ferroelectric Properties ◽  
Amorphous Fraction ◽  
Poly Vinylidene Fluoride

Oriented amorphous fraction in biaxially oriented poly(vinylidene fluoride) gives it significantly enhanced dielectric and ferroelectric properties.

W doping-dependent structural and ferroelectric properties of SrBi2Nb2O9 ferroelectric ceramics

2007 ◽  
Vol 400 (1-2) ◽  
pp. 134-136 ◽  
Author(s):  
Jie Qiu ◽  
Guo-Zhen Liu ◽  
Meng He ◽  
Hao-Shuang Gu ◽  
Tao-Sheng Zhou
Keyword(s):  
Ferroelectric Properties ◽  
Ferroelectric Ceramics ◽  
W Doping

Synthesis and Ferroelectric Properties of Sol–Gel Derived Intergrowth-Superlattice-Structured SrBi4Ti4O15-Bi4Ti3O12 Thin Films

2011 ◽  
Vol 197-198 ◽  
pp. 1781-1784
Author(s):  
Hua Wang ◽  
Jian Li ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou
Keyword(s):  
Thin Films ◽  
Remanent Polarization ◽  
Annealing Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Si Substrates ◽  
Gel Processing ◽  
Coercive Electric Field ◽  
Clockwise Hysteresis

Intergrowth-superlattice-structured SrBi4Ti4O15–Bi4Ti3O12(SBT–BIT) films prepared on p-Si substrates by sol-gel processing. Synthesized SBT–BIT films exhibit good ferroelectric properties. As the annealing temperature increases from 600°C to 700°C, the remanent polarization Prof SBT–BIT films increases, while the coercive electric field Ecdecreases. SBT–BIT films annealed at 700°C have a Prvalue of 18.9µC/cm2which is higher than that of SBT (16.8µC/cm2) and BIT (14.6µC/cm2), and have the lowest Ecof 142 kV/cm which is almost the same as that of SBT and BIT. The C-V curves of Ag/SBT-BIT/p-Si heterostructures show the clockwise hysteresis loops which reveal the memory effect due to the polarization. The memory window in C-V curve of Ag/SBT-BIT/p-Si is larger than that of Ag/SBT/p-Si heterostructure or Ag/BIT/p-Si heterostructure.

Ferroelectric C-Axis Oriented Pb5Ge3O11 Thin Films for One Transistor Memory Application

1998 ◽  
Vol 541 ◽  
Author(s):  
Tingkai Li ◽  
Fengyan Zhang ◽  
Sheng Teng Hsu
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Hysteresis Loops ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Memory Devices ◽  
Leakage Currents ◽  
Fatigue Characteristics ◽  
Ferroelectric Memory ◽  
Memory Applications

AbstractOne transistor memory devices have been proposed recently. To meet the needs of one transistor memory applications, C-axis oriented Pb5Ge3O11 (PGO) thin films were prepared using metalorganic chemical vapor deposition (MOCVD) and rapid thermal processing (RTP). It was found that the nucleation of C-axis Pb5Ge3O11 phase started at a deposition temperature below 400°C and grain growth dominated at 500°C or above. With increasing annealing temperature, the remanent polarization (Pr) and coercive field (Ec) values increased, and the hysteresis loops of the Pb5Ge3O11 films were well saturated and symmetrical after the post-annealing. The C-axis PGO thin film showed good ferroelectric properties at 5V: 2Pr and 2Ec values were 2.0 - 4.0 µC/cm2 and 90 - 110 kV/cm, respectively. The films also showed excellent fatigue characteristics: no fatigue was observed up to 1 × 109 switching cycles. The retention and imprint properties have also been studied. The leakage currents of the PGO films were 2 - 5 × 10−7 A/cm2 at 100 kV/cm and dielectric constants were 40 - 70. The high quality MOCVD Pb5Ge3O11 films can be used for single transistor ferroelectric memory devices.

Graphene Oxide as a Substrate for Biosensors: Synthesis and Characterization

2021 ◽  
Vol 324 ◽  
pp. 87-93
Author(s):  
Mohamed Adel ◽  
Abdel Hady A. Abdel-Wahab ◽  
Ahmed Abdel-Mawgood ◽  
Ahmed Osman Egiza
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Acidic Solution ◽  
Cost Effective ◽  
Sem Analysis ◽  
Visible Spectroscopy ◽  
Sem Images ◽  
Hummers Method ◽  
Uv Visible ◽  
Modified Hummers Method

Graphene oxide (GO) is an oxidized nanosheets of graphite with a 2D planar structure. GO could be readily complexed with bio-entities as it possesses many oxygen-containing functionalities on its surface. The preparation process is fast, easy, and cost-effective. It was prepared using modified Hummers’ method in acidic solution as a primary solvent and potassium permanganate as an oxidizing agent. Afterwards, it was successfully characterized by FTIR, UV-visible spectroscopy, as well as XRD and Raman spectroscopy, and finally, SEM analysis. It was observed that the formed GO is mainly composed of carbon and oxygen elements rich in oxygen functional groups. Furthermore, the existence of (001) plane in XRD interprets the complete oxidation of graphite with d-spacing 9 Å. Moreover, Raman spectroscopy displayed the sp3 carbon hybridization, besides, the ID/IG ratio is found to be 0.84, which confirms the disorder between graphene oxide layers. The SEM images also pointed out that graphene oxide sheets were regularly stacked together as flake-like structures. Accordingly, the richness of oxygen-containing functionalities was confirmed. Hence, it is appropriate to be used as a base transducer for biosensing applications.

Sign in / Sign up

Export Citation Format

Share Document