scholarly journals Bismuth zinc niobate: BZN-BT, a new lead-free BaTiO3-based ferroelectric relaxor?

2020 ◽  
Vol 10 (06) ◽  
pp. 2050033
Author(s):  
Jessica Marshall ◽  
David Walker ◽  
Pam Thomas
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Dielectric Material ◽  
Ferroelectric Properties ◽  
High Capacity ◽  
Rapid Onset ◽  
Lead Free ◽  
Cubic Phase ◽  
The Novel ◽  
Ferroelectric Relaxor

The novel lead-free ferroelectric relaxor system [Formula: see text](Bi([Formula: see text] [Formula: see text][Formula: see text](1[Formula: see text]BaTiO3 ([Formula: see text]BZN(1[Formula: see text]BT) has received interest as a high-capacity relaxor dielectric material. Small quantities (< 10.0 mol.%) of BZN-based dopant had significant impacts on the structure of the BaTiO3 host. This study evaluates the effect of BZN additions to the BaTiO3 host up to [Formula: see text]BZN = 10.0%. Initial additions of BZN were observed to stabilize tetragonal and orthorhombic coexistence at 295 K, alongside increasing dielectric constant. Peak dielectric constant and polarization were observed at [Formula: see text] < 4.0%, coinciding with maximum orthorhombic intensity and a local minima in tetragonal intensity. Compositions 0 < [Formula: see text] < 4.0% showed increasing polarization and a drop in [Formula: see text] and classical ferroelectric properties. No significant dielectric dispersion was observed for compositions [Formula: see text] < 4.0% over the frequency range 5–640 kHz. Compositions at [Formula: see text] > 4.0% showed the onset of dielectric relaxation alongside a drop in polarization coincident with a drop in the tetragonal [Formula: see text]/[Formula: see text] ratio and the onset of the cubic phase at 295 K. Peak piezoelectric, dielectric and polarization values occurred over the range 3.8% < [Formula: see text] < 4.0%, alongside maximum orthorhombic intensity. Subsequent BZN additions showed a rapid onset of dielectric relaxation, alongside an increase in cubic intensity and a continuous drop in [Formula: see text] with a minima near [Formula: see text] = 7.0%. Tetragonal presence at 295 K also vanished to zero at [Formula: see text] = 7.0%. Polarization loops ceased showing ferroelectric characteristics at [Formula: see text] > 5.0%, showing a transition from lossy relaxor dielectric to low-loss relaxor dielectric at [Formula: see text] > 10.0%.

Electrical Properties of Modified BNT Based Lead-Free Ceramics

2016 ◽  
Vol 872 ◽  
pp. 87-91
Author(s):  
Supalak Manotham ◽  
Tawee Tunkasiri ◽  
Pharatree Jaita ◽  
Pichitchai Butnoi ◽  
Denis Russell Sweatman ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Free Ceramics

The properties of modified Bi0.5Na0.5TiO3 (BNT) based lead-free ceramics were investigated. The BNT-based ceramics were prepared by a solid-state mixed oxide method Phase formation was determined by X-ray diffraction technique (XRD). The X-ray diffraction analysis of the ceramics suggested that all samples exhibited a perovskite structure without second phase. The value of dielectric constant increased with increasing in sintering temperature. Moreover, high sintering temperatures could improve ferroelectric properties of BNT base lead-free ceramics.

Dielectric and Structural Properties of RF Magnetron Sputter Grown Lead Zirconium Titanate Thin Film: A Review

2013 ◽  
Vol 667 ◽  
pp. 312-316
Author(s):  
Zainal Nurbaya ◽  
Zulkefle Habibah ◽  
Mohamad Rusop Mahmood
Keyword(s):  
Dielectric Constant ◽  
Dielectric Material ◽  
Ferroelectric Properties ◽  
Zirconium Titanate ◽  
Lead Zirconium Titanate ◽  
Current State ◽  
Rf Magnetron Sputter ◽  
Magnetron Sputter ◽  
High K Dielectric ◽  
Power Application

This review summarizes the current state of lead zirconium titanate (PZT) that used for energy storage based organic capacitor. The particular focus is on dielectric material PZT properties for achieving high-k dielectric constant (900-1300) concerning for DC power application. PZT is well known of its perovskite structure that related to excellent ferroelectric properties considered to have high remnant polarization and low coercive field. We review the recent literature that focused on the annealing process that affects dielectric constant and its structural property derived by radio frequency (RF) magnetron sputter.

scholarly journals Dielectric and Ferroelectric Properties of Lead-Free[1-z{(Bi1-xLax)0.5(Na1-yLiy)0.5TiO3}-zBaTiO3]Ceramic System

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Vijayeta Pal ◽  
R. K. Dwivedi ◽  
O. P. Thakur
Keyword(s):  
Dielectric Constant ◽  
Ferroelectric Properties ◽  
Dissipation Factor ◽  
Lead Free ◽  
Rhombohedral Structure ◽  
Nonlinear Behaviour ◽  
Ceramic System ◽  
Low Dielectric ◽  
Maximum Dielectric Constant ◽  
Xrd Patterns

Lead-free specimens of [1-z{(Bi1-xLax)0.5(Na1-yLiy)0.5TiO3}-zBaTiO3] (BLNLT-BT, wherex=0.04,y=0.025, andz=0, 0.02, 0.04, and 0.06) ceramic system were synthesized by a semiwet technique. In the present study, we have investigated the effect of Ba on the structure, morphology, and dielectric, ferroelectric, and piezoelectric properties of BLNLT system. The XRD patterns of all the specimens showed rhombohedral structure at room temperature. Field emission scanning electron microscopy images (FE-SEM) showed grain growth inhibition with Ba content in BLNLT system. The temperature dependence of dielectric constant revealed that the temperature of maximum dielectric constant “Tm” and depolarization temperature “Td” decreased for the samplez=0.06and showed high value of dielectric constant with low dielectric loss. These samples exhibited nonlinear behaviour of hysteresis loop. The values of dielectric constant (εr), dissipation factor (tan δ), piezo charge coefficient (d33), remnant polarization (Pr), and coercive field (Ec) for the compositionz=0.06were 1495, 0.06, 20 pC/N, 5 μC/cm2, and 10.5 kV/cm, respectively.

Basic Andragogy-Oriented Strategies and Communication in Online Education

2020 ◽  
Vol 26 (2) ◽  
pp. 350-356
Author(s):  
Anca Sîrbu
Keyword(s):  
Adult Learners ◽  
Online Education ◽  
Social Status ◽  
Rapid Onset ◽  
Learning Goals ◽  
The Novel ◽  
Academic Education ◽  
Online Instructors ◽  
New Methods ◽  
The World

AbstractWith the rapid onset of an unprecedented lifestyle due to the new coronavirus COVID-19 the world academic scene was forced to reform and adapt to the novel circumstances. Although online education cannot be regarded as a groundbreaking endeavour anymore in the21st century, its current character of exclusivity calls for deeper understanding of, and a sharper focus on the “end-consumer” thereof as well as more cautious procedures to be exercised while teaching. While millennials are no longer thought of as being born with a silver spoon in their mouth but with an iPad or any sort of device in their hand (irrespective of their social status), adults are more hesitant when coerced to alter course unexpectedly and turn to new methods of attaining their learning goals. This is why proper communicative approaches need to be thoroughly considered by online instructors. This article aims at presenting teachers with a set of strategies to employ when the beneficiaries of online academic education are adult learners.

Skin–core structured fluorinated MWCNTs: a nanofiller towards a broadband dielectric material with a high dielectric constant and low dielectric loss

2018 ◽  
Vol 6 (9) ◽  
pp. 2370-2378 ◽  
Author(s):  
Yang Liu ◽  
Cheng Zhang ◽  
Benyuan Huang ◽  
Xu Wang ◽  
Yulong Li ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Dielectric Material ◽  
Epoxy Composite ◽  
Low Dielectric ◽  
High Dielectric

A novel skin–core structured fluorinated MWCNT nanofiller was prepared to fabricate epoxy composite with broadband high dielectric constant and low dielectric loss.

scholarly journals 458. Molecular SARS-CoV-2 Testing During the COVID-19 Outbreak: Experiences of a Hospital in Southeast Michigan, USA

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S296-S297
Author(s):  
Trini A Mathew ◽  
Jonathan Hopkins ◽  
Diane Kamerer ◽  
Shagufta N Ali ◽  
Daniel Ortiz ◽  
...  
Keyword(s):  
Clinical Features ◽  
Diagnostic Testing ◽  
Beaumont Hospital ◽  
High Capacity ◽  
Turnaround Time ◽  
Molecular Diagnostic ◽  
The Novel ◽  
Repeat Testing ◽  
Asymptomatic Patients ◽  
Novel Coronavirus

Abstract Background The novel Coronavirus SARS CoV-2 (COVID-19) outbreak was complicated by the lack of diagnostic testing kits. In early March 2020, leadership at Beaumont Hospital, Royal Oak Michigan (Beaumont) identified the need to develop high capacity testing modalities with appropriate sensitivity and specificity and rapid turnaround time. We describe the molecular diagnostic testing experience since initial rollout on March 16, 2020 at Beaumont, and results of repeat testing during the peak of the COVID-19 pandemic in MI. Methods Beaumont is an 1100 bed hospital in Southeast MI. In March, testing was initially performed with the EUA Luminex NxTAG CoV Extended Panel until March 28, 2020 when testing was converted to the EUA Cepheid Xpert Xpress SARS-CoV-2 for quicker turnaround times. Each assay was validated with a combination of patient samples and contrived specimens. Results During the initial week of testing there was &gt; 20 % specimen positivity. As the prevalence grew the positivity rate reached 68% by the end of March (Figure 1). Many state and hospital initiatives were implemented during the outbreak, including social distancing and screening of asymptomatic patients to increase case-finding and prevent transmission. We also adopted a process for clinical review of symptomatic patients who initially tested negative for SARS-CoV-2 by a group of infectious disease physicians (Figure 2). This process was expanded to include other trained clinicians who were redeployed from other departments in the hospital. Repeat testing was performed to allow consideration of discontinuation of isolation precautions. During the surge of community cases from March 16 to April 30, 2020, we identified patients with negative PCR tests who subsequently had repeat testing based on clinical evaluation, with 7.1% (39/551) returning positive for SARS- CoV2. Of the patients who expired due to COVID-19 during this period, 4.3% (9/206) initially tested negative before ultimately testing positive. Figure 1 BH RO testing Epicurve Figure 2: Screening tool for repeat COVID19 testing and precautions Conclusion Many state and hospital initiatives helped us flatten the curve for COVID-19. Our hospital testing experience indicate that repeat testing may be warranted for those patients with clinical features suggestive of COVID-19. We will further analyze these cases and clinical features that prompted repeat testing. Disclosures All Authors: No reported disclosures

scholarly journals Transport and Dielectric Properties of Mechanosynthesized La2/3Cu3Ti4O12 Ceramics

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 313
Author(s):  
Mohamad M. Ahmad ◽  
Hicham Mahfoz Kotb ◽  
Celin Joseph ◽  
Shalendra Kumar ◽  
Adil Alshoaibi
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Boundary Conductivity ◽  
X Ray ◽  
Giant Dielectric ◽  
Mechanochemical Milling ◽  
Giant Dielectric Constant ◽  
Lower Temperature

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

scholarly journals Study of charge transfer mechanism and dielectric relaxation of all-inorganic perovskite CsSnCl3

RSC Advances ◽  
2021 ◽  
Vol 11 (35) ◽  
pp. 21767-21780
Author(s):  
Mohamed Ben Bechir ◽  
Mohamed Houcine Dhaou
Keyword(s):  
Charge Transfer ◽  
Dielectric Relaxation ◽  
Monoclinic Phase ◽  
Conduction Mechanism ◽  
Small Polaron ◽  
Cubic Phase ◽  
Inorganic Perovskite ◽  
Charge Transfer Mechanism ◽  
Large Polaron ◽  
Olpt Model

The conduction mechanism in CsSnCl3 is interpreted through the following two approaches: the non-overlapping small polaron tunneling (NSPT) model (monoclinic phase) and the overlapping large polaron tunneling (OLPT) model (cubic phase).

The Research on the Piezoelectric and Dielectric Properties of Bi0.5(Nak)0.5-BaTiO3 Lead-Free Ceramics

2014 ◽  
Vol 1035 ◽  
pp. 422-425
Author(s):  
Jian Yong Guo ◽  
Tao Sheng Zhou ◽  
Ji Hong Liao
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Perovskite Structure ◽  
Relative Dielectric Constant ◽  
Lead Free ◽  
Reactive Sintering ◽  
Lead Free Ceramics ◽  
Xrd Patterns ◽  
Sintering Method

The Bi0.5(Na1-xKx)0.5-yBaTiO3(BNK-BT) lead-free ceramics have been prepared by the solild reactive sintering method. XRD patterns show the BNK-BT ceramics had a perovskite structure. Piezoelectric and dielectric properties of the ceramics also have been studied. The results show that the samples had the best piezoelectric and dielectric properties when x=0.20, y=0.10. And the maximum of d33is 149 pC/N, while the relative dielectric constant is 1087.

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