LEFT-HANDED MAXWELLIAN BEHAVIOR OF NATURAL MICA

2011 ◽  
Vol 25 (30) ◽  
pp. 2323-2333
Author(s):  
ADITI SARKAR ◽  
ARNAB GANGOPADHYAY ◽  
A. SARKAR
Keyword(s):  
Monochromatic Light ◽  
Polarized Light ◽  
X Ray Diffraction ◽  
Optical Reflectance ◽  
Optical Absorbance ◽  
Left Handed ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Dc Current ◽  
Theoretical Results

In this work, meta-material like behavior of natural Mica are studied. This work makes an attempt to analyze the left-handed Maxwellian (LHM) properties of Mica. The investigations carried out on natural Mica specimen are optical reflectance, optical absorbance and DC current–voltage-characteristics (CVC). Optical reflectance of Mica sheet with plane polarized monochromatic light shows distinct difference with conventional theoretical results. The DC CVC also measured with complete electromagnetic shielding. There exists a clear difference in DC characteristic for presence and absence of stray electromagnetic fields. The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-VIS) analysis are also carried out for further analysis. The results obtained from the optical reflectance characteristics using polarized light indicate LHM behavior as may be found in a meta-material. Micro-structural and electrical analysis shows that it is a nano-structured layered material.

Characterization of Gd2O3 Nano Clusters

2013 ◽  
Vol 665 ◽  
pp. 127-131
Author(s):  
Somnath Paul ◽  
Arnab Gangopadhyay ◽  
A. Sarkar
Keyword(s):  
Thermal Dissociation ◽  
Gadolinium Oxide ◽  
Magnetic Element ◽  
Optical Absorbance ◽  
Current Voltage ◽  
Sensitivity Studies ◽  
Current Voltage Characteristics ◽  
Dc Current ◽  
Average Cluster

Gadolinium (Gd) is a weak magnetic element at room temperature. Gadolinium oxide (Gd2O3) is a poor semiconductor with para-magnetism. In this work Gadolinium oxide is prepared from the thermal dissociation of Gadolinium acetate. The average cluster size is found to be dependent on the number of the sintering time. In this present work an attempt has been made to characterize the developed Gadolinium oxide. Experimental probes used to characterize it are optical absorbance (UV-VIS); Fourier transformed infra red (FTIR) spectroscopy, DC current voltage characteristics (CVC) and photo-sensitivity studies of the developed specimens. Gadolinium oxide exhibits a good optical sensing property.

Grain Boundary Atomic Structures in SrTiO3 and BaTiO3

2007 ◽  
Vol 558-559 ◽  
pp. 851-856 ◽  
Author(s):  
Takahisa Yamamoto ◽  
Teruyasu Mizoguchi ◽  
S.Y. Choi ◽  
Yukio Sato ◽  
Naoya Shibata ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Annealing Temperature ◽  
Unit Length ◽  
Rate Dependency ◽  
Atomic Structures ◽  
Current Voltage ◽  
Single Grain ◽  
Current Voltage Characteristics ◽  
Theoretical Results

SrTiO3 bicrystals with various types of grain boundaries were prepared by joining two single crystals at high temperature. By using the bicrystals, we examined their current-voltage characteristics across single grain boundaries from a viewpoint of point defect segregation in the vicinity of the grain boundaries. Current-voltage property in SrTiO3 bicrystals was confirmed to show a cooling rate dependency from annealing temperature, indicating that cation vacancies accumulate due to grain boundary oxidation. The theoretical results obtained by ab-initio calculation clearly showed that the formation energy of Sr vacancies is the lowest comparing with Ti and O vacancies in oxidized atomosphere. The formation of a double Schottky barrier (DSB) in n-type SrTiO3 is considered to be closely related to the accumulation of the charged Sr vacancies. Meanwhile, by using three types of low angle boundaries, the excess charges related to one grain boundary dislocation par unit length was estimated. In this study, we summarized our results obtained in our group.

ELECTROMECHANICAL CHARACTERISTICS OF POLYVINYLIDENE FLUORIDE FOR FLEXIBLE ELECTRONICS

2013 ◽  
Vol 37 (3) ◽  
pp. 325-333 ◽  
Author(s):  
Wen-Yang Chang ◽  
Cheng-Hung Hsu
Keyword(s):  
Flexible Electronics ◽  
Polyvinylidene Fluoride ◽  
Input Voltage ◽  
Pvdf Film ◽  
Resistive Load ◽  
X Ray Diffraction ◽  
Leakage Currents ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Stress Cycles

The electromechanical characteristics of PVDF are investigated, including the crystallization, frequency responses, hysteresis, leakage currents, current-voltage characteristics, and fatigue characteristics using X-ray diffraction and an electrometer. Results show that the frequency band of PVDF increases with increasing resistive load and capacitance. The hysteresis area of ΔH slightly increases with increasing input voltage. The magnitude of the current values increases with decreasing delay time at a given drive voltage. PVDF film induced larger degradation when the number of stress cycles was increased to about 105 cumulative cycles.

Negative Differential Resistance of Graphene Oxide/Sulphur Compound

2021 ◽  
Vol 67 ◽  
pp. 25-31
Author(s):  
Sophia R. Figarova ◽  
Elvin M. Aliyev ◽  
Rashad G. Abaszade ◽  
R.I. Alekberov ◽  
Vagif R. Figarov
Keyword(s):  
Graphene Oxide ◽  
Functional Groups ◽  
Negative Differential Resistance ◽  
Characteristic Curve ◽  
Differential Resistance ◽  
Localized States ◽  
Sulphur Compound ◽  
X Ray Diffraction ◽  
Current Voltage ◽  
Current Voltage Characteristics

Graphene oxide/sulphur compound was synthesized by Hammers method. The chemical composition, presence/quantity of functional groups, exfoliation level, number of layers, crystallite size of graphene oxide/sulphur were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy images. The current-voltage characteristics of the samples were measured in air at room temperature. In the I - V characteristic curve of graphene oxide/sulphur compound with the ratio of oxygen to carbon of 3.54 and that to sulphur of 42.54, negative differential resistance was observed. The negative differential resistance is attributed to current carrier transitions between the localized states formed by functional groups.

Study of the Effect of Metal/Semiconductor Interface Properties on a Resistance Switching Device

2007 ◽  
Vol 997 ◽  
Author(s):  
Manuel Villafuerte ◽  
Silvia P. Heluani ◽  
Gabriel Juárez ◽  
David Comedi ◽  
Gabriel Braunstein ◽  
...  
Keyword(s):  
Resistance Switching ◽  
Electrical Contacts ◽  
X Ray Diffraction ◽  
Semiconductor Interface ◽  
Si Substrates ◽  
Barrier Heights ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Terminal Structure ◽  
Gap States

AbstractN-doped ZnO thin films were deposited by pulsed laser deposition on SiO2/Si substrates. X-ray diffraction analysis revealed that the films had the wurtzite structure, and were highly oriented along the c-axis direction. Au and Al electrical contacts were deposited by sputtering on the top surface of the samples, forming a two-terminal structure in each case. The current-voltage characteristics of the two terminal structure, and the temperature dependence of the resistance switching effect, were studied in the 125-300 K temperature range. The results of these measurements are presented and discussed in terms of the different Schottky barrier heights, as well as in terms of interfacial defect-induced gap states.

Rectifying characteristics and tunable magnetoresistance in heterojunctions of La0.9Hf0.1MnO3/0.05 wt.% Nb-doped SrTiO3

2017 ◽  
Vol 31 (25) ◽  
pp. 1745022 ◽  
Author(s):  
Yaping Qi ◽  
Xiangbo Liu ◽  
Hao Ni ◽  
Ming Zheng ◽  
Liping Chen ◽  
...  
Keyword(s):  
Band Structure ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Ferromagnetic Transition ◽  
Grown Film ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Current Voltage ◽  
Current Voltage Characteristics

La[Formula: see text]Hf[Formula: see text]MnO3 films were grown on 0.05 wt.% Nb-doped SrTiO3 substrates by pulsed laser deposition. X-ray diffraction measurements demonstrated that our samples were of good epitaxy and single-crystal. The temperature-dependent resistance has been investigated. It was observed that the as-grown film of La[Formula: see text]Hf[Formula: see text]MnO3 exhibited a typical paramagnetic-ferromagnetic transition. Heterojunctions of La[Formula: see text]Hf[Formula: see text]MnO3/0.05 wt.% Nb-doped SrTiO3 exhibited-asymmetric current–voltage characteristics and a remarkable temperature-dependent rectifying behavior in a wide temperature range (from 40 K to 300 K). And the most remarkable observation of this work is the existence of a crossover from positive to negative magnetoresistance in the La[Formula: see text]Hf[Formula: see text]MnO3/0.05 wt.% Nb-doped SrTiO3 heterojunction as the temperature decreases. A temperature-dependent magnetoresistance was studied as well. The rectifying characteristics and tunable magnetoresistance of these heterojunctions may be attributed to band structure of La[Formula: see text]Hf[Formula: see text]MnO3/0.05 wt.% Nb-doped SrTiO3 heterojunction.

Sol–Gel Synthesized SnO2 Nanoparticles and Their Properties

2007 ◽  
Vol 7 (12) ◽  
pp. 4402-4411 ◽  
Author(s):  
Soumen Das ◽  
Soumen Basu ◽  
Gautam Majumdar ◽  
Dipankar Chakravorty ◽  
S. Chaudhuri
Keyword(s):  
Sno2 Nanoparticles ◽  
Sol Gel ◽  
Binding Energies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optical Absorbance ◽  
Atomic Force ◽  
Transmission Electron ◽  
Average Size ◽  
Theoretical Results

Sol–gel synthesized SnO2 nanoparticles with an average size of 2.0 nm obtained at 373 K were gradually annealed to 673 K in air for 25 minutes. Sequentially taken transmission electron microscopy (TEM) images showed that particle agglomeration of these non-matrix SnO2 nanocrystals was a very slow process. The blue shifts of the band gap (∼ 2.3 eV) obtained from the optical absorbance spectra were matched with the theoretical results of the size related excitonic binding energies. These calculations also supported the observed slow grain growth. The depth sensitive hardness measurements of the thin films indicated hardness in the range of 5.03 GPa to 6.79 GPa. These undoped and non-matrix SnO2 nanoparticles were also investigated with the X-ray photoelectrons spectroscopy (XPS), atomic force microscope (AFM), X-ray diffraction spectroscopy (XRD), and ac impedance analyzer.

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