Ahmed, Arham S.Gupta, JhalakAnwer, Abdul HakeemKhan, Mohammad Zain...
15页查看更多>>摘要：A facile sol-gel ultrasonication route has been adopted for synthesizing Co3O4/NiO nanocomposite series, which has been analyzed for their dielectric and electrochemical properties and compared with their components i.e. NiO & Co3O4. The synthesised specimens were characterized using various experimental techniques such as XRay diffraction (XRD), Scanning electron microscope (SEM) with Energy dispersive X-Ray Spectroscopy (EDX), X-Ray Photoelectron Spectroscopy (XPS), Transmission electron Microscopy (TEM). The frequency dependence of dielectric parameters in the range varying from 75 kHz to 5 MHz at room temperature has been explored. The variation of the a. c. conductivity, dielectric constant and loss factor with frequency were investigated. The loss tangent and dielectric constant exhibited a decreasing behaviour with increasing frequency. The samples having low values of loss at higher frequency indicate that these synthesised samples can be employed in high frequency applications. The nanocomposite samples exhibit improved electrochemical properties than their components. They were used as electrode materials of energy storage devices and found to deliver improved specific capacitance and cycling stability. The synthesised samples were found to exhibit high values of power and energy density. The nanocomposite sample (with 40% NiO) has lowest value of charge transfer co-efficient indicating the anodic current is dominant.
原文链接:
NSTL
Elsevier
Zou, ZhengchunZhou, PanTan, RuiLi, Wenqi...
6页查看更多>>摘要：It is generally believed that conductivity plateaus can only exist in the insulators with topological nontrivial bulk occupied states. Such rule exhibits in two-dimensional quantum (anomalous) Hall effect, quantum spin Hall effect, and three-dimensional topological insulators. In this work, we propose spin Hall conductivity (SHC) plateau can be formed in three-dimensional metallic materials with triply degenerate points around the Fermi level. With the help of a four-band k.p model, we prove that SHC plateaus can be formed between vertical bar 3/2, +/- 3/2 and vertical bar 1 2, +/- 1 2 states of a metallic systems. Our further ab initio calculations reveal that a nearly ideal SHC plateau exhibits in an experimentally synthesized TaN. The plateau width reaches up to 0.55 eV, hoping to work at high temperatures. The electrical conductivity tensors of TaN indicates that its spin Hall angle reaches -0.57, which is larger than many previous reported materials and makes it an excellent candidate to produce stable spin current.
原文链接:- NSTL
- Elsevier
Solovev, P. N.Skomorokhov, G., VIzotov, A., VBelyaev, B. A....
7页查看更多>>摘要：Thin magnetic films with periodic surface topography are of special interest for microwave applications as their static and dynamic magnetic characteristics can be readily adjusted. In this paper, we explore the capabilities of a simple method for producing large-area periodically patterned films by creating regularly spaced grooves on a substrate using a diamond cutter. For 110-nm-thick films, it was found that the substrate-topography-induced magnetic anisotropy was inversely proportional to the pattern period, which in experimental samples varied from 5 to 20 mu m. Based on the Netzelmann theory, analytical expressions for demagnetization tensor components were obtained, which accord well with the experimental data. The measurements of the natural ferromagnetic resonance spectra demonstrated that the increase of the topography-induced magnetic anisotropy with the decrease of the pattern period led to the increase of the resonance frequency from 0.65 to 1.86 GHz, and to a decrease of the linewidth and effective damping parameter.
原文链接:- NSTL
- Elsevier
Hashimoto, KentaKawaji, HitoshiKitani, Suguru
4页查看更多>>摘要：We investigate herein the thermal transport properties of Cu1-xZnxIr2S4 (0 < x < 0.3). The thermal conductivity of CuIr2S4 exhibits an abrupt change during the metal-insulator transition (MIT). This change is attributed to a 59% decrease in phonon thermal conductivity kappa ph from the insulating phase to the metallic phase (MP). Specifically, a kappa ph of x = 0.05 and 0.1 shows a decrease at the MIT temperature. However, the decrease at the MIT temperature reduces with an increase in the Zn substitution. At x = 0.3, the MIT is almost suppressed. The decrease in kappa ph is attributed to a significant decrease in the phonon mean free path l, suggesting that anomalous phonon scattering is introduced additionally in the MP. Furthermore, l in the MP increases with increasing Zn substitution from x = 0.05 to 0.3, and this suggests that the anomalous phonon scattering in the MP is suppressed by Zn substitution.
原文链接:- NSTL
- Elsevier
Tromer, Raphael M.Woellner, Cristiano F.Tiwary, Chandra S.Galvao, Douglas S....
7页查看更多>>摘要：Pentadiamond is a recently proposed new carbon allotrope consisting of a network of pentagonal rings where both sp2 and sp3 hybridization are present. In this work we investigated the mechanical and electronic properties, as well as, the thermal stability of pentadiamond using DFT and fully atomistic reactive molecular dynamics (MD) simulations. We also investigated its properties beyond the elastic regime for three different deformation modes: compression, tensile and shear. The behavior of pentadiamond under compressive deformation showed strong fluctuations in the atomic positions which are responsible for the strain softening at strains beyond the linear regime, which characterizes the plastic flow. As we increase temperature, as expected, Young's modulus values decrease, but this variation (up to 300 K) is smaller than 10% (from 347.5 to 313.6 GPa), but the fracture strain is very sensitive, varying from -44% at 1 K to -5% at 300 K.
原文链接:- NSTL
- Elsevier
Pandey, VarunKumar, Munish
7页查看更多>>摘要：A simple theory based on the bond energy model is developed. The model is used to study the bulk modulus of different nanomaterials. A good agreement between theory and experiments demonstrates the suitability of the model proposed. Due to simplicity and applicability of the model, we extended the theory to study the size and shape dependence of bulk modulus of different nanomaterials. The results have been compared with the earlier theoretical work and available experimental data. It is concluded that the model predicts better agreement with the earlier work as far as experimental studies are concerned. Due to the predicting capability, the model is extended to different nanomaterials of current interest to study their elastic behaviour under varying conditions of size and shape. To the best of our knowledge, such a simple model is not yet available in the literature, which works well from bulk to nanoscale.
原文链接:- NSTL
- Elsevier
Li, KailiWang, XueyouZeng, HongyanSa, Rongjian...
5页查看更多>>摘要：The structural, electronic and optical properties of Zn1-xHgxSe alloys with different Hg concentrations (x = 0, 0.25, 0.50, 0.75, 1) are studied through first-principles calculations. The stability of three Zn1-xHgxSe ternary alloys is proved by calculating phonon spectrum. It is found that the SOC effect on the band gap is less than 0.2 eV. In addition, the HSE06 functional underestimates the band gap of ZnSe, so the PBE0 functional is employed to calculate the electronic and optical properties of Zn1-xHgxSe alloys. The tunable band gap can be realized by Hg doping from 2.5 to 0 eV Zn0.75Hg0.25Se and Zn0.50Hg0.50Se have suitable band gaps (1.0-1.8 eV) for solar cells. Zn0.50Hg0.50Se shows wider and higher absorption coefficient than that of Zn0.75Hg0.25Se in the visible light range.
原文链接:- NSTL
- Elsevier
