scholarly journals SYNTHESIS AND DIELECTRIC PROPERTIES OF La0.67LixTi1-xAlxO3 (0.15≤x≤0.3) CERAMICS

2020 ◽  
Vol 86 (11) ◽  
pp. 13-23
Author(s):  
Tatiana Plutenko ◽  
Oleg V'yunov ◽  
Boris Khomenko ◽  
Anatolii Belous
Keyword(s):  
Wide Frequency Range ◽  
Aluminum Concentration ◽  
Lithium Aluminum ◽  
Frequency Range ◽  
Solid State Reaction Technique ◽  
Cole Diagram ◽  
Impedance Spectroscopy Study ◽  
High Dielectric Permittivity ◽  
High Dielectric ◽  
Very High

Solid solutions of Al-doped lithium lanthanum titanates La0.67LixTi1-xAlxO3 system (where 0.15 ≤ x ≤ 0.3) have been synthesized by solid-state reaction technique. Light optical microscopy has shown that the grain size of La0.67LixTi1-xAlxO3 ceramics insignificantly increases with an increase in lithium/aluminum concentration. The materials La0.67LixTi1-xAlxO3 show very high dielectric permittivity ε΄ 104 over a relatively wide frequency range (102 ≤ f ≤ 104 Hz) with no apparent dependence on the x. The impedance spectroscopy study indicates three semicircles on Cole-Cole diagram that can be attributed to electrically different areas of ceramic’s grain.

scholarly journals Thermoplastic Polyurethane/Lead Zirconate Titanate/Carbon Nanotube Composites with Very High Dielectric Permittivity and Low Dielectric Loss

2020 ◽  
Vol 4 (3) ◽  
pp. 137
Author(s):  
Gayaneh Petrossian ◽  
Nahal Aliheidari ◽  
Amir Ameli
Keyword(s):  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Lead Zirconate Titanate ◽  
Thermoplastic Polyurethane ◽  
Lead Zirconate ◽  
Low Dielectric ◽  
High Dielectric Permittivity ◽  
Tan Δ ◽  
High Dielectric ◽  
Very High

Ternary composites of flexible thermoplastic polyurethane (TPU), lead zirconate titanate (PZT), and multiwalled carbon nanotubes (MWCNTs) with very high dielectric permittivity (εr) and low dielectric loss (tan δ) are reported. To assess the evolution of dielectric properties with the interactions between conductive and dielectric fillers, composites were designed with a range of content for PZT (0–30 vol%) and MWCNT (0–1 vol%). The microstructure was composed of PZT-rich and segregated MWCNT-rich regions, which could effectively prevent the formation of macroscopic MWCNT conductive networks and thus reduce the high ohmic loss. Therefore, εr increased by a maximum of tenfold, reaching up to 166 by the addition of up to 1 vol% MWCNT to TPU/PZT. More importantly, tan δ remained relatively unchanged at 0.06–0.08, a similar range to that of pure TPU. εr/tan δ ratio reached 2870 at TPU/30 vol% PZT/0.5 vol% MWCNT, exceeding most of the reported values. This work demonstrates the potential of three-phase polymer/conductive filler/dielectric filler composites for efficient charge storage applications.

A new single/few-layered graphene oxide with a high dielectric constant of 106: contribution of defects and functional groups

RSC Advances ◽  
2015 ◽  
Vol 5 (19) ◽  
pp. 14768-14779 ◽  
Author(s):  
K. Santhosh Kumar ◽  
Suresh Pittala ◽  
Srinath Sanyadanam ◽  
Pradip Paik
Keyword(s):  
Dielectric Constant ◽  
Graphene Oxide ◽  
Dielectric Permittivity ◽  
Functional Groups ◽  
High Dielectric Constant ◽  
Frequency Range ◽  
Temperature Range ◽  
High Dielectric Permittivity ◽  
High Dielectric

In this study, we introduce a single/few-layered graphene oxide (GO) synthesized with ultrasonication, and demonstrate its high dielectric permittivity in the frequency range of 20 Hz to 2 MHz and temperature range of 30 °C to 180 °C.

Perceptual discrimination of very high frequency components in wide frequency range musical sound

2009 ◽  
Vol 70 (7) ◽  
pp. 921-934 ◽  
Author(s):  
Toshiyuki Nishiguchi ◽  
Kimio Hamasaki ◽  
Kazuho Ono ◽  
Masakazu Iwaki ◽  
Akio Ando
Keyword(s):  
High Frequency ◽  
Wide Frequency Range ◽  
Perceptual Discrimination ◽  
Frequency Range ◽  
Very High Frequency ◽  
Musical Sound ◽  
Frequency Components ◽  
Very High

scholarly journals Enhanced dielectric properties with a significantly reduced loss tangent in (Mg2+, Al3+) co-doped CaCu3Ti4O12 ceramics: DFT and experimental investigations

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 25038-25046
Author(s):  
Jakkree Boonlakhorn ◽  
Jedsada Manyam ◽  
Sriprajak Krongsuk ◽  
Prasit Thongbai ◽  
Pornjuk Srepusharawoot
Keyword(s):  
Dielectric Properties ◽  
Liquid Phase ◽  
Loss Tangent ◽  
Liquid Phase Sintering ◽  
Experimental Investigations ◽  
Low Loss ◽  
High Dielectric Permittivity ◽  
High Dielectric ◽  
Very High ◽  
Co Doped

Mg and Al atoms preferentially occupy Cu sites, creating liquid-phase sintering decomposition at grain boundary layers. This results in very high dielectric permittivity and a low loss tangent of the CaCu2.95Mg0.05Ti3.95Al0.05O12 ceramic.

The Giant Dielectric Constant of Y2NiMnO6 Ceramics for DC Bias

2017 ◽  
Vol 866 ◽  
pp. 277-281
Author(s):  
Naphat Albutt ◽  
Suejit Pechprasarn ◽  
Pattaraporn Damkoengsuntorn ◽  
Thanapong Sareein
Keyword(s):  
Dielectric Constant ◽  
Dielectric Permittivity ◽  
Room Temperature ◽  
Frequency Range ◽  
Electronic Components ◽  
Giant Dielectric ◽  
High Dielectric Permittivity ◽  
Dc Bias ◽  
Giant Dielectric Constant ◽  
High Dielectric

In this work, the uses of giant dielectric constant of Y2NiMnO6 ceramics were investigated in the frequency range from 1 kHz to 3 MHz. The Y2NiMnO6 ceramics were sintered at 1400 °C for 6, 12, 18 and 24 hours, respectively. The dielectric properties of Y2NiMnO6 ceramics were examined in dc bias from 0 to 1.5 volt at room temperature. We found that all sintering times displayed high dielectric permittivity at frequencies below 105 Hz, above which the values decreased significantly, applied dc bias also reduced dielectric permittivity. The peak of dielectric loss decreased significantly at high dc bias due to decreased contribution of dc conductivity in grain ceramics. This research has characterised electrical properties of Y2NiMnO6 ceramics which maybe suitable for electronic components including batteries and capacitors.

Electrical and Magnetic Properties of (BiLi)1/2(FeV)1/2O3

2011 ◽  
Vol 110-116 ◽  
pp. 5437-5441
Author(s):  
Subrat K. Barik ◽  
Sudipta K. Bera
Keyword(s):  
Single Phase ◽  
Complex Impedance ◽  
Polycrystalline Sample ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Phase Compound ◽  
Different Temperatures

The polycrystalline sample of (BiLi) 1/2 (FeV) 1/2O3 was prepared by a high-temperature solid-state reaction technique. A preliminary X-ray structural analysis exhibited the formation of single-phase compound with an orthorhombic structure. Detailed studies of electrical properties of the compound, investigated in a wide frequency range (1kHz-1MHz) at different temperatures by complex impedance spectroscopy (CIS) technique, showed that these properties of the material are strongly dependent on frequency and temperature. Ac conductivity is found to obey the Johnscher’s law. The M-H curve shows the presence of ferromagnetism in the studied compound.

scholarly journals Investigation of Grain Size Effect on the Impedance of CaCu3Ti4O12 from 100 Hz to 1 GHz of Frequency

2012 ◽  
Vol 620 ◽  
pp. 230-235 ◽  
Author(s):  
Muhammad Azwadi Sulaiman ◽  
Sabar Derita Hutagalung ◽  
Zainal Arifin Ahmad ◽  
Mohd Fadzil Ain
Keyword(s):  
Dielectric Constant ◽  
Barrier Layer ◽  
Room Temperature ◽  
High Dielectric Constant ◽  
Perovskite Phase ◽  
Wide Frequency Range ◽  
Treatment Temperature ◽  
Domain Boundaries ◽  
High Dielectric ◽  
Very High

CaCu3Ti4O12(CCTO) is a cubical perovskite phase and sintered ceramics exhibit very high dielectric constant at room temperature. The speculated origins of the high dielectric constant are the existence of insulative barrier layer at grain boundaries and domain boundaries which created an internal barrier layer capacitance (IBLC) at the microstructure of CCTO. The relation of grains and domains electrical resistance were studied in this work by using impedance spectroscopy (IS). A series of samples with different heat treatment temperature were tested to investigate their microstructure by using field emission scanning electron microscopy (FESEM). The grains and domains resistance was calculated from a wide frequency range of impedance complex plane measurement (100 Hz to 1 GHz). The FESEM and IS analyses showed the dependency of grains and domains resistance to average grains size of CCTO microstructure.

scholarly journals Dielectric elastomers, with very high dielectric permittivity, based on silicone and ionic interpenetrating networks

RSC Advances ◽  
2015 ◽  
Vol 5 (61) ◽  
pp. 49739-49747 ◽  
Author(s):  
Liyun Yu ◽  
Frederikke Bahrt Madsen ◽  
Søren Hvilsted ◽  
Anne Ladegaard Skov
Keyword(s):  
Dielectric Permittivity ◽  
Dielectric Elastomers ◽  
Interpenetrating Networks ◽  
High Dielectric Permittivity ◽  
High Dielectric ◽  
Very High

Dielectric elastomers (DEs), which represent an emerging actuator and generator technology, admittedly have many favourable properties, but their high driving voltages are one of the main obstacles to commercialisation.

scholarly journals Materials with high dielectric permeability on the basis of spontaneously polarized systems, lithium conductors and transition metal oxides

2021 ◽  
pp. 67-78
Author(s):  
Anatolii G. Belous ◽  
◽  
Oleg I. V'yunov ◽  
Oleg Z. Yanchevskii ◽  
Leonid L. Kovalenko ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Wide Frequency Range ◽  
Dielectric Losses ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Low Frequencies ◽  
Low Dielectric ◽  
Constant E ◽  
High Dielectric

Materials with a high dielectric constant (e > 1000) based on complex oxides of spontaneously polarized systems, lithium-conducting systems, and oxides of transition metals were studied. It was shown in dielectric ceramics Ba(Ti,Sn)O3 the absence of significant dispersion of dielectric parameters (e and tg δ) in a wide frequency range from 1 to 105 Hz. The introduction of MnO2 and Al2O3-SiO2-TiO2 improves dielectric parameters and reduces sintering temperature. Obtained ceramic materials are characterized by high dielectric constant values e ~ 13000–16000 and low dielectric losses tg d ~ 0.05–0.06 (at 1 MHz). Synthesized solid solutions of La0.5Li0.5-xNaxTiO3 system, where x = 0 and 0.1, have high values e¢ > 104 at low frequencies (f ≤ 10 Hz). Dielectric properties of these materials are determined by the lithium ions mobility that increases with the rise of sodium content by increasing bottleneck size and decreases by the number of lithium vacancies reduction. The disadvantage of such materials is the decrease in dielectric constant with frequency increase. It was found that the ceramic СaСu3Тi4–xAlxО12-y-0.5xFy with x/y = 0.04/0.04 after sintering for 10 h is characterized by dielectric parameters: e¢ » 71000 (1 kHz) and tg d » 0.047. Introduction of aluminum (x/y = 0.04/0) or fluorine (0/0.08) in CCTO reduces dielectric losses (tg d » 0.044). The advantages of this type of material are a wide frequency range of high dielectric constant and relatively low dielectric loss. Synthesized materials can be used for the development of ceramic capacitors with high characteristics.

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