scholarly journals Влияние термообработки на электрические характеристики полуизолирующих слоев, полученных с помощью облучения n-SiC высокоэнергетическими ионами аргона

2018 ◽  
Vol 44 (6) ◽  
pp. 11 ◽  
Author(s):  
П.А. Иванов ◽  
А.С. Потапов ◽  
М.Ф. Кудояров ◽  
М.А. Козловский ◽  
Т.П. Самсонова
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Room Temperature ◽  
High Energy ◽  
Room Temperature Resistivity ◽  
Electrical Characteristics ◽  
Near Surface ◽  
Heat Treated ◽  
Argon Ions ◽  
Temperature Resistivity

AbstractIrradiation of crystalline n -type silicon carbide ( n -SiC) with high-energy (53-MeV) argon ions was used to create near-surface semi-insulating ( i -SiC) layers. The influence of subsequent heat treatment on the electrical characteristics of i -SiC layers has been studied. The most high-ohmic ion-irradiated i -SiC layers with room-temperature resistivity of no less than 1.6 × 10^13 Ω cm were obtained upon the heat treatment at 600°C, whereas the resistivity of such layers heat-treated at 230°C was about 5 × 10^7 Ω cm.

Preparation of Ni/BaTiO3 Composites and PTC Effect

2007 ◽  
Vol 280-283 ◽  
pp. 341-344
Author(s):  
Xiao Lei Li ◽  
Yuan Fang Qu ◽  
Wei Bing Ma ◽  
Zhan Shen Zheng
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Room Temperature Resistivity ◽  
Ptc Effect ◽  
Reducing Atmosphere ◽  
Prepared Composite ◽  
Temperature Resistivity ◽  
Ntc Effect

Ni/BaTiO3 composite was prepared by decomposition of NiC2O4·2H2O/BaTiO3 precursor, which was prepared by precipitating of nickel in the form of oxalate into the BaTiO3 slurry. The composite must be sintered in reducing atmosphere. Otherwise NTC effect would be introduced. The prepared composite almost had no PTC effect. But PTC effect of the Ni/BaTiO3 composite can be effectively renewed by heat-treatment in air. Under a proper composition and method, the composite shows low room-temperature resistivity (ρRT=6.0 Ω·cm) and obvious PTC effect (ρmax/ρmin=102).

Study of Resistance Characteristics of Silicon Carbide Resistor Materials

2012 ◽  
Vol 724 ◽  
pp. 17-20
Author(s):  
Hai Yun Jin ◽  
Da Wei Feng ◽  
Zhen Huang ◽  
Rui Dong Niu ◽  
Rong Zhen Liu ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Particle Size ◽  
Electron Microscope ◽  
Room Temperature ◽  
Volume Resistivity ◽  
Experimental Program ◽  
Room Temperature Resistivity ◽  
Preparation Technology ◽  
Temperature Resistivity ◽  
Scanning Electron

Experimental program and preparation technology of highly densified reaction bonded silicon carbide resistance materials with different resistivity were investigated by using alumina or silicon nitride as aids for improving of the volume resistivity. The microstructure of the materials was observed by scanning electron microscope. According to the experimental results, the resistivity of the material could be controlled by the particle size and the content of the aids. Besides, alumina could reduce silicon penetration and increase resistivity greatly, and 10wt.% of alumina could satisfy the requirement of resistance. In addition, different particle size of matrix materials had a great impact on the resistivity. Compared with the coarse silicon carbide, the room temperature resistivity value by using the fine silicon carbide could increases for six times.

Complex Analysis of Electrical Resistivity Dynamics of Co82Fe4Cr3Si8B3 Amorphous Alloy under Heat Treatment

2013 ◽  
Vol 811 ◽  
pp. 72-76 ◽  
Author(s):  
Aleksandr Kotvitckii ◽  
Galina Kraynova ◽  
Anatoly Frolov ◽  
Vitaly Ivanov
Keyword(s):  
Heat Treatment ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Amorphous Alloy ◽  
Room Temperature ◽  
Complex Analysis ◽  
Room Temperature Resistivity ◽  
Resistivity Minimum ◽  
Temperature Resistivity ◽  
Amorphous Character

In this paper the detailed analysis of thermal behavior of electrical resistivity of Co82Fe4Cr3Si8B3 amorphous alloy is made. It has been shown that within temperature range 230С <T< 5600С the structure of the alloy keeps its amorphous character and only a slight changes occurred. A high temperature (above room temperature) resistivity minimum was found at 160°C. This feature was related with Curie temperature of the alloy. It has been shown that change of electrical resistivity behavior at 350°C can be explained by reaching the Debye temperature of the alloy.

SYNTHESIS OF NANOSIZE SILICON CARBIDE POWDER BY CARBOTHERMAL REDUCTION OF SiO2

2012 ◽  
Vol 05 ◽  
pp. 263-269 ◽  
Author(s):  
M. DEHGHANZADEH ◽  
A. ATAIE ◽  
S. HESHMATI-MANESH
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Phase Composition ◽  
Crystalline Silicon ◽  
High Energy ◽  
Nano Particles ◽  
Process Conditions ◽  
Sample Heat ◽  
State Reduction ◽  
Heat Treated

A mixture of silicon carbide nano-particles and nano-whiskers has been synthesized through solid state reduction of silica by graphite employing high energy planetary ball milling for 25 h and subsequent heat treatment at 1300-1700°C in dynamic argon atmosphere. Effects of process conditions on the thermal behavior, phase composition and morphology of the samples were investigated using DTA/TGA, XRD and SEM, technique, respectively. DTA/TGA analysis shows that silicon carbide starts to form at ~ 1250°C. Analysis of the XRD patterns indicates that the phase composition of the sample heat treated at 1300°C for 2 h mainly consists of SiO 2 together with small amount of β- SiC . Nano-crystalline silicon carbide phase with a mean crystallite size of 38 nm was found to be dominate phase on heat treatment temperature at ~ 1500°C. Substantial SiO 2 was still remained in the above sample. SEM studies reveal that the sample heat treated at 1500°C for 2 h contains nano-particles and nano-whisker of β- SiC with a mean diameter of almost ~ 85 nm. The results obtained were also showed that the characteristics of the synthesized SiC particles strongly depend on the mechanical activation and heat treatment conditions.

The Influence of Heat Treatment on the Electrical Characteristics of Semi-Insulating SiC Layers Obtained by Irradiating n-SiC with High-Energy Argon Ions

2018 ◽  
Vol 44 (3) ◽  
pp. 229-231 ◽  
Author(s):  
P. A. Ivanov ◽  
A. S. Potapov ◽  
M. F. Kudoyarov ◽  
M. A. Kozlovskii ◽  
T. P. Samsonova
Keyword(s):  
Heat Treatment ◽  
High Energy ◽  
Electrical Characteristics ◽  
Argon Ions

scholarly journals Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 660
Author(s):  
Susana Devesa ◽  
Joana Rodrigues ◽  
Sílvia Soreto Teixeira ◽  
Aidan P. Rooney ◽  
Manuel P. F. Graça ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Optical Properties ◽  
Room Temperature ◽  
Sol Gel ◽  
High Energy ◽  
Site Symmetry ◽  
Photoluminescence Spectra ◽  
Heat Treated ◽  
Red Color ◽  
Optical Activation

Tetragonal Er0.5Nb0.5O2 and monoclinic ErNbO4 micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO4 revealed a spherical-shaped crystallite, whose size increased with heat treatment temperatures. To assess their optical properties at room temperature (RT), a thorough spectroscopic study was conducted. RT photoluminescence (PL) spectroscopy revealed that Er3+ optical activation was achieved in all samples. The photoluminescence spectra show the green/yellow 2H11/2, 4S3/2→4I15/2 and red 4F9/2→4I15/2 intraionic transitions as the main visible recombination, with the number of the crystal field splitting Er3+ multiplets reflecting the ion site symmetry in the crystalline phases. PL excitation allows the identification of Er3+ high-energy excited multiplets as the preferential population paths of the emitting levels. Independently of the crystalline structure, the intensity ratio between the green/yellow and red intraionic transitions was found to be strongly sensitive to the excitation energy. After pumping the samples with a resonant excitation into the 4G11/2 excited multiplet, a green/yellow transition stronger than the red one was observed, whereas the reverse occurred for higher excitation photon energies. Thus, a controllable selective excited tunable green to red color was achieved, which endows new opportunities for photonic and optoelectronic applications.

Influence of Modulation Wavelength Induced Order on the Physical Properties of Nb/Rare Earth Superlattices

1984 ◽  
Vol 37 ◽  
Author(s):  
L. H. Greene ◽  
W. L. Feldmann ◽  
J. M. Rowell ◽  
B. Batlogg ◽  
R. Hull ◽  
...  
Keyword(s):  
Rare Earth ◽  
Room Temperature ◽  
Room Temperature Resistivity ◽  
Residual Resistance ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Residual Resistance Ratio ◽  
Temperature Resistivity ◽  
Modulation Wavelength

AbstractWe report the observation of a higher degree of preferred crystalline orientation in Nb/rare earth superlattices for modulation wavelengths in the range of 200 Å to 500 Å than that exhibited by single component films. All films and multilayers are sputter deposited onto room temperature sapphire substrates. Electronic transport measurements also show that the residual resistance ratio is higher and the room temperature resistivity is lower than for multilayers of either greater or lower periodicities. Transmission electron micrographs (TEM) showing excellent layering, grain size comparable to the layer thickness, and evidence of some degree of epitaxy are presented.

scholarly journals Computational Intelligence Approach for Estimating Superconducting Transition Temperature of Disordered MgB2Superconductors Using Room Temperature Resistivity

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Taoreed O. Owolabi ◽  
Kabiru O. Akande ◽  
Sunday O. Olatunji
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Room Temperature ◽  
Optimization Technique ◽  
Support Vector ◽  
Measuring Instruments ◽  
Room Temperature Resistivity ◽  
Superconducting Transition ◽  
Experimental Values ◽  
Temperature Resistivity

Doping and fabrication conditions bring about disorder in MgB2superconductor and further influence its room temperature resistivity as well as its superconducting transition temperature (TC). Existence of a model that directly estimatesTCof any doped MgB2superconductor from the room temperature resistivity would have immense significance since room temperature resistivity is easily measured using conventional resistivity measuring instrument and the experimental measurement ofTCwastes valuable resources and is confined to low temperature regime. This work develops a model, superconducting transition temperature estimator (STTE), that directly estimatesTCof disordered MgB2superconductors using room temperature resistivity as input to the model. STTE was developed through training and testing support vector regression (SVR) with ten experimental values of room temperature resistivity and their correspondingTCusing the best performance parameters obtained through test-set cross validation optimization technique. The developed STTE was used to estimateTCof different disordered MgB2superconductors and the obtained results show excellent agreement with the reported experimental data. STTE can therefore be incorporated into resistivity measuring instruments for quick and direct estimation ofTCof disordered MgB2superconductors with high degree of accuracy.

Effect of Heat Treatment Condition on the Characteristics of MnO2 Added-Fe2TiO5 Ceramics for NTC Thermistors Using Local Iron Oxide

2018 ◽  
Vol 917 ◽  
pp. 64-68
Author(s):  
Wiendartun ◽  
Jaenudin Kamal ◽  
Dadi Rusdiana ◽  
Andhy Setiawan ◽  
Dani Gustaman Syarief
Keyword(s):  
Heat Treatment ◽  
Iron Oxide ◽  
Treatment Condition ◽  
Treatment Time ◽  
Heat Treatment Condition ◽  
Heat Treatment Time ◽  
Second Phase ◽  
Room Temperature Resistivity ◽  
Electrical Characteristics ◽  
Ntc Thermistor

A study on the effect of heat treatment condition on the characteristics of MnO2 added-Fe2TiO5 ceramics for NTC thermistor has been carried out. The ceramics were produced by pressing an homogenous mixture of Fe2O3 (local/ yarosite), TiO2 and MnO2 (2.0 mole %) powders in appropriate proportions to produce Fe2TiO5 based ceramics and sintering the pressed powder at 1050 °C for 3 hours in oxygen gas. Some sintered pellets were heat treated by heating them at 300 °C for 5, 15 and 25 minutes in Ar + 7% H2 gas. The XRD analyses showed that the Fe2TiO5 ceramics with and without heat treatment time had orthorhombic structure. No peak from second phase was observed from the XRD profiles. From the electrical characteristics data, it was known that the heat treatment could change the electrical characteristics of the Fe2TiO5 based-thermistor. The thermistor constant (B) and room temperature resistivity (ρRT) decreased with the increasing of heat treatment time. All ceramics made had thermistor characteristics namely B = 3459-7596 K and ρRT = 1.056-6936.062 MΩcm. Thermistor constant of the ceramics was relatively big, indicated that ceramics made from local iron oxide in this work fit the market requirement for NTC thermistor.

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