scholarly journals Investigation of The Dielectric Properties Of (Cu, Tl) 1234 Added with Graphene

2019 ◽  
Vol 13 (4) ◽  
pp. 12
Author(s):  
Ibrahim. Younes ◽  
Hadi. Basma ◽  
Mohamad. Anas ◽  
Ramadan. Awad
Keyword(s):  
Dielectric Properties ◽  
Normal Pressure ◽  
Superconducting Transition ◽  
Solid State Reaction Technique ◽  
Sem Images ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
One Step ◽  
Dielectric Constant Increase ◽  
Frequency Temperature

Superconducting samples of type (Cu­0.5Tl0.5)-1234 were prepared at normal pressure via one step of conventional solid state reaction technique, and added with x wt.% of graphene (0≤x≤0.1). X-ray powder diffraction (XRD) shows that the addition of graphene does not alter the tetragonal structure and the lattice parameters of the samples. Fourier Transform Infrared (FTIR) measurements indicate the non-uniform distribution of graphene inside the (Cu­0.5Tl0.5)-1234 phase. While the Scanning Electron Microscope (SEM) images reveal the increase of the inter-grain connectivity. The superconducting transition temperature Tc, obtained from Ac magnetic susceptibility measurements, shows an enhancement up to x=0.04 Wt. %, followed by a deterioration for x >0.04. The frequency dependence of the dielectric properties of the samples was experimentally investigated at different temperatures (110 K ≤ T ≤ 260 K). The real and imaginary parts (ε' and ε'') of dielectric constant increase up to x=0.1. The study of ε' and ε'', the dielectric loss (tan δ) and the ac-conductivity (σac) have shown that the variation of frequency, temperature and addition of graphene allows the tuning of these parameters for various applications.

Preparation and Characterization of NTC NiMn2O4-La1-xCaxMnO3 (0≤x≤0.3) Composite Ceramics

2013 ◽  
Vol 716 ◽  
pp. 78-83 ◽  
Author(s):  
Hui Min Zhang ◽  
Fang Guan ◽  
Ai Min Chang ◽  
Li Jun Zhao
Keyword(s):  
Electrical Resistivity ◽  
Perovskite Structure ◽  
Spinel Structure ◽  
Thermal Constant ◽  
Inrush Current ◽  
Composite Ceramics ◽  
Sem Images ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
Xrd Patterns

Composite ceramics made of spinel structure NiMn2O4 and CaO-doped perovskite structure LaMnO3 were prepared by a conventional solid state reaction and sintered at different temperatures. The XRD patterns have shown that the major phases presented in the sintered samples are NiMn2O4 compounds with the spinel structure, La1-xCaxMnO3 with the perovskite structure and NiO with a monoclinic structure. SEM images show that the density and grain size of the composite ceramics increases with sintered temperature increasing. The electrical resistivity of the composite ceramics at 25°C is found to change significantly depending on the CaO content, while the thermal constant B is still reasonably large in the range of 2400 to 3000 K. For the composition x = 0.1, the composite with a low electrical resistivity (ρ25°C=4.46Ω·cm) and moderate B value (B25/50=2762K) was obtained. These composites could be applied as potential candidates for NTC thermistors in the suppression of the inrush current.

Electrical Properties of a High-Tc Superconductor-Polymer Compersite

2007 ◽  
Vol 546-549 ◽  
pp. 1989-1992
Author(s):  
Fang Gao Chang ◽  
Kun Fang ◽  
Gui Lin Song
Keyword(s):  
Annealing Temperature ◽  
Solid State Reaction Method ◽  
Gravimetric Analysis ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Different Temperatures ◽  
Zero Resistance ◽  
Composite Samples

A superconductor-polymer composite of Bi1.8Pb0.4Sr2Ca2Cu3Oy and ethylene propylene rubber (EPR) was prepared by conventional solid-state reaction method. The phase structure of the composite was characterized by using x-ray diffraction technique. The resistivity of composite samples annealed at different temperatures was measured between 40K and 300K. The results indicate that the resistivity of the as-prepared composite increases with increasing EPR content and shows essentially a semiconducting behavior above Tc. For fixed EPR content, the resistivity of composite samples decreases with increasing annealing temperature. The composite begins to show some signs of superconducting transition at an annealing temperature of 700 °C and zero resistance is reached for samples sintered at 800°C. Thermal gravimetric analysis (TGA) on the composite confirmed that 65% of the EPR content still present in the superconducting composite samples. SEM was used to investigate the surface morphology of the composites. Preliminary results show that the mechanical properties of the composite have been much improved compared with its parent superconductor ceramics.

Effect of Sintering Temperature on Properties of Multiferroic BaFe12O19/MgFe2O4/BaTiO3 Composites

2016 ◽  
Vol 846 ◽  
pp. 410-415
Author(s):  
M.F.A. Zolkepli ◽  
Rozidawati Awang ◽  
Zalita Zainuddin
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
Tetragonal Batio

In this paper, the structural, magnetic and electrical properties of multiferroic BaFe12O19/MgFe2O4/BaTiO3 composites have been studied. BaFe12O19/MgFe2O4/BaTiO3 composites were synthesized by using the conventional solid state reaction technique and sintered at different temperatures. XRD analysis confirmed the existence of hexagonal BaFe12O19, cubic spinel MgFe2O4 and tetragonal BaTiO3 for ferrites and ferroelectric phases, respectively. The suitable sintering temperature for preparing BaFe12O19/MgFe2O4/BaTiO3 composites is between 1000 °C and 1050 °C. SEM analysis showed that as a whole the grain size increases and the pores is reduced with sintering temperature; thus the sample became denser. The coercive field and saturation magnetization decreases when sintering temperature is increased. Resistance of the samples decrease from 103 kW to 19 kW while the capacitance increases from 0.8 nF to 4.0 nF with sintering temperature.

Structural and Dielectric Properties of Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2012 ◽  
Vol 585 ◽  
pp. 219-223
Author(s):  
Rekha Kumari ◽  
N. Ahlawat ◽  
Ashish Agarwal ◽  
M. Sindhu ◽  
N.N. Ahlawat
Keyword(s):  
Dielectric Properties ◽  
Solid State Reaction Method ◽  
Wide Frequency Range ◽  
Ferroelectric Ceramics ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
X Ray ◽  
Different Temperatures

Na0.5Bi0.5TiO3 (NBT) ceramics were synthesized by conventional solid state reaction method. Structural and dielectric properties of these ceramics were investigated. Crystalline phase of sintered ceramics was investigated by X-ray diffraction (XRD). The Rietveld refinement of powder X-ray diffraction revealed that the prepared ceramics exhibit the rhombohedral space group R3c. Dielectric properties of Na0.5Bi0. analyzer.5TiO3 (NBT) ceramics were studied at different temperatures in a wide frequency range using impedance

scholarly journals A CLOSE CORRELATION BETWEEN DISORDERS-DEFECTS AND SUPERCONDUCTING TRANSITION TEMPERATURE OF Bi1.6Pb0.4Sr2Ca2-xNaxCu3O10+δ SUPERCONDUCTORS

2018 ◽  
Vol 56 (1A) ◽  
pp. 41
Author(s):  
Tran Hoai Duc
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Volume Fraction ◽  
Close Correlation ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Conventional Solid State Reaction ◽  
Residual Resistance ◽  
Residual Resistance Ratio

The enhancements of zero superconducting transition temperature (Tc,0) in Bi1.6Pb0.4Sr2Ca2-xNaxCu3O10+δ(BPSCCO) are reported. The BPSCCO samples (with x ranging from 0.00 to 0.06) were prepared by using the conventional solid state reaction technique. The properties of the samples were examined by using the X-ray diffraction (XRD), scanning electron microscopy (SEM), and the resistance versus temperature (R-T) measurements. From the XRD resuts, all samples revealed the orthorhombic structure, and the volume fraction of the Bi-2223 phase was varied as increasing x, and reached the maximum value of  82.72 % for x = 0.05 sample. Improvements of connectivity between the Bi-2223 grains in the Na-substituted BPSCCO samples were obtained by using the surface SEM images and a quantitive analysis of a correlation between Tc,0 and residual resistance ratio (RRR). A similar variation of  Tc,0 of the samples as increasing x was observed. The highest Tc,0 enhancement of 107.5 K was obtained for x = 0.05 sample. Variations of the hole carrier concentrations in the CuO2 layers were investigated, which also showed the highest value achieved for x = 0.05 sample.

HREM study on the structure of SrMnO3-x with planar defect

1990 ◽  
Vol 48 (4) ◽  
pp. 488-489
Author(s):  
Hiroyasu Shibahara
Keyword(s):  
Layer Structure ◽  
Oxygen Deficiency ◽  
Normal Pressure ◽  
Planar Defect ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Planar Defects ◽  
Octahedral Sites ◽  
Bright Contrast ◽  
Calculated Image

The system of SrMnO3-x is known to be layered structure closely related to that of perovskite with oxygen deficiency and based on a stacking of close- packed SrO3 layers with Mn metals occupying interlayer octahedral sites, SrMnO3 possesses a 4-layer structure with hexagonal stacking (sequence of “ABAC”) at normal pressure, and through a 6-layer structure (“ABCACB”) transform into a 3-layer structure with cubic stacking at higher pressure, Based on the observed images with HREM (JEM-2000EX) showing an irregular stacking along c-axis, the distribution and the origin of planar defect were discussed.Specimens of SrMnO3-x were prepared by the conventional solid-state reaction technique . The typical observed image of 4H structure along 010 direction is shown in Fig.l together with the calculated image. The planar defects were often observed in the sample as shown in Fig.2, in which they represent a bright contrast. The defects were classified by their characteristic in image contrast into the three classes (type A,B and C), which are indicated by the marks in Fig.2.

scholarly journals Influence of Cu on the Improvement of Magnetic Properties and Structure of L10 FePt Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1097
Author(s):  
Luran Zhang ◽  
Xinchen Du ◽  
Hongjie Lu ◽  
Dandan Gao ◽  
Huan Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Annealing Temperature ◽  
Reduction Method ◽  
Solid Phase ◽  
Average Particle Size ◽  
Fept Nanoparticles ◽  
Average Particle ◽  
Phase Reduction ◽  
Different Temperatures ◽  
One Step

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.

Investigation of Dielectric Properties of TiO2 and Al2O3 nanofluids by Frequency Domain Spectroscopy at Different Temperatures

2021 ◽  
Vol 330 ◽  
pp. 115642
Author(s):  
B. Chakraborty ◽  
K.Y. Raj ◽  
A.K. Pradhan ◽  
B. Chatterjee ◽  
S. Chakravorti ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Frequency Domain ◽  
Different Temperatures

scholarly journals Microwave Sintering and Microwave Dielectric Properties of (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 Ceramics

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 438
Author(s):  
Shuwei Yang ◽  
Bingliang Liang ◽  
Changhong Liu ◽  
Jin Liu ◽  
Caisheng Fang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mobile Communications ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Dielectric Properties ◽  
Conventional Heating ◽  
Sintering Process ◽  
Microwave Dielectric ◽  
Sintering Time ◽  
Frequency Temperature

The (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 [(1–x)CLT-xNMT, x = 0.35~0.60] ceramics were prepared via microwave sintering. The effects of sintering temperature and composition on the phase formation, microstructure, and microwave dielectric properties were investigated. The results show that the microwave sintering process requires a lower sintering temperature and shorter sintering time of (1–x)CLT-xNMT ceramics than conventional heating methods. All of the (1–x)CLT-xNMT ceramics possess a single perovskite structure. With the increase of x, the dielectric constant (ε) shows a downward trend; the quality factor (Qf) drops first and then rises significantly; the resonance frequency temperature coefficient (τf) keeps decreasing. With excellent microwave dielectric properties (ε = 51.3, Qf = 13,852 GHz, τf = −1.9 × 10−6/°C), the 0.65CLT-0.35NMT ceramic can be applied to the field of mobile communications.

Effect of the BSCCO superconducting properties by tiny Y2O3 addition

2016 ◽  
Vol 30 (26) ◽  
pp. 1650328
Author(s):  
Yan Dong ◽  
Aimin Sun ◽  
Bin Xu ◽  
Hongtao Zhang ◽  
Meng Zhang
Keyword(s):  
Volume Fraction ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Critical Transition Temperature ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Oxide Addition ◽  
One Step ◽  
Step Transition ◽  
Y2o3 Addition

In this paper, the effect of tiny Y2O3 addition in (Bi,[Formula: see text]Pb)-2223 superconductor prepared by solid state reaction technique was studied. The properties of samples have been investigated via X-ray diffraction (XRD), resistance–temperature ([Formula: see text]–[Formula: see text]) curve, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). XRD data indicated that all samples are multiphase and the major phases are high-temperature phases and low-temperature phases. The volume fraction of (Bi,[Formula: see text]Pb)-2223 is not great change with tiny Y2O3 addition. All samples exhibit superconducting phase with the critical transition temperature and one-step transition, however, the transition width was decreased with the Y2O3 addition up to 0.04 wt.% and sharp increased with the excessive oxide addition. SEM pictures show that the Y2O3 appeared on the flake-type grains surface obviously, but the number and size of the hole between grains are decreased in the 0.04 wt.% addition.

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