Selection guidelines for ionic dielectrics with gigantic dielectric response (GDR) based on polaronic phase transition criteria

2013 ◽  
Vol 1535 ◽  
Author(s):  
Valeri Ligatchev ◽  
Zhigen Yu ◽  
Jianwei Zheng ◽  
Michael B. Sullivan
Keyword(s):  
Phase Transition ◽  
Dielectric Response ◽  
Physical Nature ◽  
Dielectric Materials ◽  
Physical Mechanisms ◽  
Transition Criteria ◽  
Temperature Ranges ◽  
Experimental And Theoretical Studies ◽  
Very High ◽  
Selection Of

ABSTRACTDielectric materials with GDR (e.g. CaCu3Ti4O12 – CCTO and isostructural systems, co-doped NiO etc) attract major research interest due to their bright prospective in energy storage and memory devices. However, after years of intensive experimental and theoretical studies of GDR materials, physical nature of their extremely high complex dielectric permittivity (specifically, real part ∼ 104 - 106) is still not established convincingly. Another serious problem is excessively high imaginary part of the permittivity (which usually exceeds real one). Better understanding on physical mechanisms and limitations of GDR behavior in aforementioned dielectrics could be achieved based on polaronic phase transition criteria, proposed S. Fratini and P. Quémerais [Eur. Phys. Journ. B14, 99 (2000)]. In particular, ‘melting’ of Polaronic Wigner Crystal (PWC) either to ‘polaronic liquid’ or ‘electron liquid’ manifests two different scenarios of PWC phase transition at increment of concentrations of appropriate dopants. The former scenario is certainly preferable for ionic dielectrics with GDR behavior, while the latter one would yield in metal-like dielectric response with very high real permittivity, but unacceptable loss. Described approach provides physically transparent guidelines for selection of prospective host dielectrics with GDR behavior and quantitative estimations on critical dopant/polaron concentrations, corresponding to both aforementioned types of the phase transitions as well as temperature ranges suitable for GDR.

Current-Signature-Based Analysis of Complex Test Fails

1999 ◽  
Author(s):  
Anne E. Gattiker ◽  
Phil Nigh ◽  
Wojciech Maly
Keyword(s):  
Failure Analysis ◽  
Physical Nature ◽  
Channel Length ◽  
Test Methods ◽  
Multiple Test ◽  
Physical Mechanisms ◽  
Test Behavior ◽  
Complex Test ◽  
Current Signature ◽  
Insight Into

Abstract This article provides an analysis of a class of failures observed during the SEMATECH-sponsored Test Methods Experiment. The analysis focuses on use of test-based failure analysis and IDDQ signature analysis to gain insight into the physical mechanisms underlying such subtle failures. In doing so, the analysis highlights techniques for understanding failure mechanisms using only tester data. In the experiment, multiple test methods were applied to a 0.45 micrometer effective channel length ASIC. Specifically, ICs that change test behavior from before to after burn-in are studied to understand the physical nature of the mechanism underlying their failure. Examples of the insights provided by the test-based analysis include identifying cases where there are multiple or complex defects and distinguishing cases where the defect type is likely to be a short versus an open and determining if the defect is marginal. These insights can be helpful for successful failure analysis.

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

scholarly journals Germanium Nanowires as Sensing Devices: Modelization of Electrical Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 507
Author(s):  
Luca Seravalli ◽  
Claudio Ferrari ◽  
Matteo Bosi
Keyword(s):  
Charge Transfer ◽  
Electrical Properties ◽  
Surface Charges ◽  
Molecular Sensing ◽  
Germanium Nanowires ◽  
Physical Mechanisms ◽  
Additional Doping ◽  
Different Types ◽  
N Doping ◽  
Very High

In this paper, we model the electrical properties of germanium nanowires with a particular focus on physical mechanisms of electrical molecular sensing. We use the Tibercad software to solve the drift-diffusion equations in 3D and we validate the model against experimental data, considering a p-doped nanowire with surface traps. We simulate three different types of interactions: (1) Passivation of surface traps; (2) Additional surface charges; (3) Charge transfer from molecules to nanowires. By analyzing simulated I–V characteristics, we observe that: (i) the largest change in current occurs with negative charges on the surfaces; (ii) charge transfer provides relevant current changes only for very high values of additional doping; (iii) for certain values of additional n-doping ambipolar currents could be obtained. The results of these simulations highlight the complexity of the molecular sensing mechanism in nanowires, that depends not only on the NW parameters but also on the properties of the molecules. We expect that these findings will be valuable to extend the knowledge of molecular sensing by germanium nanowires, a fundamental step to develop novel sensors based on these nanostructures.

scholarly journals The Primary Origin of Excellent Dielectric Properties of (Co, Nb) Co-Doped TiO2 Ceramics: Electron-Pinned Defect Dipoles vs. Internal Barrier Layer Capacitor Effect

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3230
Author(s):  
Theeranuch Nachaithong ◽  
Narong Chanlek ◽  
Pairot Moontragoon ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Loss Tangent ◽  
Barrier Layer ◽  
Dielectric Response ◽  
High Resistivity ◽  
Low Loss ◽  
Rutile Tio2 ◽  
Complex Defect ◽  
Very High ◽  
Co Doped

(Co, Nb) co-doped rutile TiO2 (CoNTO) nanoparticles with low dopant concentrations were prepared using a wet chemistry method. A pure rutile TiO2 phase with a dense microstructure and homogeneous dispersion of the dopants was obtained. By co-doping rutile TiO2 with 0.5 at.% (Co, Nb), a very high dielectric permittivity of ε′ » 36,105 and a low loss tangent of tanδ » 0.04 were achieved. The sample–electrode contact and resistive outer-surface layer (surface barrier layer capacitor) have a significant impact on the dielectric response in the CoNTO ceramics. The density functional theory calculation shows that the 2Co atoms are located near the oxygen vacancy, creating a triangle-shaped 2CoVoTi complex defect. On the other hand, the substitution of TiO2 with Nb atoms can form a diamond-shaped 2Nb2Ti complex defect. These two types of complex defects are far away from each other. Therefore, the electron-pinned defect dipoles cannot be considered the primary origins of the dielectric response in the CoNTO ceramics. Impedance spectroscopy shows that the CoNTO ceramics are electrically heterogeneous, comprised of insulating and semiconducting regions. Thus, the dielectric properties of the CoNTO ceramics are attributed to the interfacial polarization at the internal insulating layers with very high resistivity, giving rise to a low loss tangent.

Temperature-triggered order–disorder phase transition in molecular-ionic material N-butyldiethanolammonium picrate monohydrate

RSC Advances ◽  
2016 ◽  
Vol 6 (73) ◽  
pp. 69546-69550 ◽  
Author(s):  
Tariq Khan ◽  
Muhammad Adnan Asghar ◽  
Zhihua Sun ◽  
Chengmin Ji ◽  
Lina Li ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Dielectric Materials ◽  
Disorder Phase Transition ◽  
First Order ◽  
Oxygen Atoms

We report an organic–ionic material that undergoes a first-order structural phase transition, induced by order–disorder of oxygen atoms in picrate anion. This strategy offers a potential pathway to explore new switchable dielectric materials.

Experimental and theoretical studies of structural phase transition in a novel polar perovskite-like [C2H5NH3][Na0.5Fe0.5(HCOO)3] formate

2016 ◽  
Vol 45 (6) ◽  
pp. 2574-2583 ◽  
Author(s):  
Maciej Ptak ◽  
Mirosław Mączka ◽  
Anna Gągor ◽  
Adam Sieradzki ◽  
Alessandro Stroppa ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Theoretical Studies ◽  
Experimental And Theoretical Studies

We report the synthesis and studies of a novel heterometallic formate [C2H5NH3][Na0.5Fe0.5(HCOO)3].

PSXII-2 Identification of candidate SNPs associated with high prolificacy in Romanov sheep

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 254-255
Author(s):  
Alexey V Shakhin ◽  
Arsen V Dotsev ◽  
Tatiana E Deniskova ◽  
Gottfried Brem ◽  
Natalia A Zinovieva
Keyword(s):  
Higher Education ◽  
Genetic Basis ◽  
Reference Genome ◽  
Unique Property ◽  
Candidate Snps ◽  
Merino Sheep ◽  
Sheep Breeds ◽  
Important Trait ◽  
Very High ◽  
Selection Of

Abstract Prolificacy is a very important trait in sheep. Romanov sheep, the well-known Russian sheep breed, are characterized by very high prolificacy; however, the genetic basis of this unique property of Romanov sheep is still unknown. It was reported that Ovine BMPR1B gene, located on the OAR6, is associated with prolificacy in several sheep breeds. The aim of our study was to identify candidate SNPs within BMPR1B gene, related to prolificacy. To achieve this goal, using NGS technology, we sequenced ovine BMPR1B gene in Romanov sheep (n = 6), which are characterized by high prolificacy (about 270 lambs per 100 ewes). The sequences of BMPR1B gene of Noire du Velay, Tan, Southdown and Australian Horned Merino sheep breeds as well as Asiatic mouflon (n = 1), which are characterized by significantly lower prolificacy (from 110 to 180 lambs per 100 ewes) were derived from publicly available sources and used for comparison. FST analysis performed in PLINK 1.9 program revealed 10 SNPs with values higher than 0.8. The majority of candidate SNPs under putative selection were localized in the region from 29,382,098 to 29,430,387 on OAR6 of Ovine reference genome (Oar_v3.1 (Ensembl release 98). Thus, we can suggest, that this region of the BMPR1B gene can be considered as the putative region, associated with high prolificacy of Romanov sheep. Additional studies will be needed to confirm the effect of identified candidate SNPs on prolificacy traits. The research results will be useful for artificial selection of sheep with higher prolific capacity, including the introduction of desired alleles in sheep populations using genome editing technologies. This work was supported by the Russian Ministry of Science and Higher Education No. 0445-2019-0024 and RFBR No. 20-516-56002.

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