Tahmineh Jalali, Abdolrasoul Gharaati and Mohammad Rastegar
In this paper, employing of one-dimensional magnetophotonic crystals in infrared wavelengths range is considered. For this purpose, magnetophotonic multilayer structures, composed of magnetic defect layer surrounded by dielectric and MO Bragg mirrors, have been proposed. Ce:YIG with an optical thickness in the range of 0 to λs was used as a magnetic material. By using four by four transfer matrix method, the transmittance values and Faraday rotation (FR) angles of these structures were computed. The electric field distribution was obtained by Finite Element Method (FEM). By investigation of transmittance and FR angle of magnetophotonic crystals, it was possible to design the optimized structures with a rotation larger than 30 degrees and high transmittance. Such structures with a few micrometer thickness and fast magneto-optical (MO) responses have the potential to be used in MO devices like integrated photonic elements and sensors.
Solid polymer electrolytes based on polyvinyl alcohol (PVA) doped with LiPF6 have been prepared using solution casting technique. Electrical properties of prepared electrolyte films were analyzed using AC impedance spectroscopy. The ionic conductivity was found to increase with increasing salt concentration. The maximum conductivity of 8.94 × 10−3 S·cm−1 was obtained at ambient temperature for the film containing 20 mol% of LiPF6. The conductivity enhancement was correlated to the enhancement of available charge carriers. The formation of a complex between the polymer and salt was confirmed by Fourier transform infrared spectroscopy (FT-IR). The optical nature of the polymer electrolyte films was analyzed through UV-Vis spectroscopy.
M. Mahdi, A. Djabri, M. M. Koc, R. Boukhalfa, M. Erkovan, Yu. Chumakov and F. Chemam
The full potential linearized augmented plane wave method (FLAPW) including the spin-orbit coupling has been used to study the structural, electronic and magnetic properties of GdCo5 compound. The calculations were performed within the local spin density approximation (LSDA) as well as Coulomb corrected LSDA + U approach. The study revealed that the LSDA + U method gave a better representation of the band structure, density of states and magnetic moments than LSDA. It was found that the spin magnetic moment of Co (2c) and Co (3g) atoms in the studied compound is smaller compared to the one in bulk Co. The optical and magneto-optical properties and the magneto-optical Kerr effect have also been investigated.
Mohammad Abu Haija, Georgia Basina, Fawzi Banat and Ahmad I. Ayesh
Spinel ferrite nanoparticles in the form CuFe2O4 were tested for gas sensing applications. Nanoparticles pressed in a disk form were used to construct conductometric gas sensors. The disk was placed between two electrical electrodes wherein the top electrode had a grid structure. The produced sensors were tested against H2S and H2 gases and they were found to be selective and sensitive to H2S concentration as low as 25 ppm. The composition of the nanoparticles was confirmed by X-ray diffraction and energy dispersive X-ray spectroscopy measurements. The crystal structure was verified by both X-ray diffraction and transmission electron microscope. The observations obtained from the experiments demonstrated the high potential of using CuFe2O4 nanoparticles for H2S sensing applications.
The article presents the analysis of methods for selecting dimensions of bone wedge for high tibial osteotomy. The existing methods are described along with the procedure. In the following paragraphs, deficiencies in the selection of bone wedge dimensions and global trends in this field have been demonstrated. Based on the numerical analysis, the problem appearing in the wrong choice of bone wedge dimensions was illustrated.
Dinara Sobola, Pavel Kaspar, Alois Nebojsa, Dušan Hemzal, Lubomír Grmela and Steve Smith
This study focuses on the description of oxidation of CdTe monocrystal surfaces after selective chemical etching. Measurements of surface morphology of the oxides occurring in short time are valuable for deeper understanding of the material degradation and fabrication of reliable devices with enhanced performance. The samples with (1 1 1) orientation were selectively etched and cleaned of oxide. Exposure of the oxide-free surfaces of CdTe to air at normal atmospheric conditions over 24 hours leads to an appearance of characteristic surface features. The oxidized surfaces were investigated by scanning electron microscopy, scanning probe microscopy, Raman spectroscopy and ellipsometry. The results indicate clear differences in the oxidation of Cd-terminated and Te-terminated surfaces.
M. Kucinska, M.Z. Szymanski, I. Frac, F. Chandezon and J. Ulanski
Charge-carrier transport in the channel of bottom gate, top contact organic field effect transistors with anisotropic layers of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pentacene) obtained by zone casting was investigated using scanning Kelvin probe microscopy combined with atomic force microscopy. The TIPS-Pentacene continuous layers consisted of thin crystals unidirectionally oriented in the channel. Devices with perpendicular and parallel charge flow in the transistor channel were prepared. It was found that irregularities in the surface morphology at the semiconductor layer in the transistor channel are correlated with the local potential profile, and that the channel resistance strongly depends on the orientation of the TIPS-Pentacene crystals.
Denis Sokol, Maksim Ivanov, Andrei N. Salak, Robertas Grigalaitis, Juras Banys and Aivaras Kareiva
Magnesium-aluminum-bismuth layered double hydroxides (Mg3Al1−xBix; LDHs) were prepared using both coprecipitation and sol-gel methods. For the preparation of Mg/Al/Bi LDH by the co-precipitation method, the appropriate amounts of dissolved starting materials (Al(NO3)3 · 9H2O, Mg(NO3)2 · 6H2O and Bi(NO3)3 · 5H2O) were mixed with a solution of NaHCO3:NaOH. In the sol-gel processing, the precursor Mg–Al–Bi–O gels were synthesized using the same starting materials and ethylene glycol as complexing agent. The mixed-metal oxides obtained by subsequent heating of Mg–Al–Bi–O gels at 650 °C were reconstructed to Mg3Al1−xBix LDHs in water at 80 °C. All the synthesized products were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and dielectric measurements.
W.C. Shen, L.L. Lin, C.Y. Shen, S. Xing and Z.B. Pan
TbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy (0 ⩽ x ⩽ 0.40) composites are fabricated in the presence of a magnetic field. The structural and dynamic magnetoelastic properties are investigated as a function of both magnetic bias field Hbias and frequency f at room temperature. The composites are formed as textured orientation structure of 1–3 type with 〈1 0 0〉 preferred orientation for x ⩽ 0.10 and 〈1 1 1〉-orientation for x ⩾ 0.25. The composites generally possess insignificant eddy-current losses for frequency up to 50 kHz, and their dynamic magnetoelastic properties depend greatly on Hbias. The elastic modulus (E3H and E3B) shows a maximum negative ΔE effect, along with a maximum d33, at a relatively low Hbias ~ 80 kA/m, contributed by the maximum motion of non-180° domain-wall. The 1–3 type composite for x ⩾ 0.25 shows an enhanced magnetoelastic effect in comparison with 0 to 3 type one, which can be principally ascribed to its easy magnetization direction (EMD) towards 〈1 1 1〉 axis and the formation of 〈1 1 1〉-texture-oriented structure in the composite. These attractive dynamic magnetoelastic properties, e.g., the low magnetic anisotropy and d33,max as high as 2.0 nm/A at a low Hbias ~ 80 kA/m, along with the light rare-earth Nd element existing in insulating polymer matrix, would make it a promising magnetostrictive material system.
The present work reports the effect of Cu addition on the melting point, hardness and electrical resistivity of Sn-57 wt.% Bi eutectic solder alloy. Both binary eutectic Sn-57 wt.% Bi and ternary Sn-(57-x)Bi-xCu (x = 0.1, 0.3, 0.5, 0.7 and 1 wt.%) alloys containing various amounts of Cu were developed by melting casting route. The microstructure of the various solder alloys was analyzed using an optical microscope and a SEM. The variation in melting point, hardness and electrical resistivity of the Sn-Bi eutectic solder alloys with the addition of Cu was determined. The melting point of the eutectic Sn-Bi solder alloy was found to decrease up to the addition of 0.7 wt.% Cu. However, further addition of Cu led to an increase in the melting point of the alloy. Addition of Cu led to an increase in the hardness of the eutectic Sn-Bi solder alloy whereas the electrical resistivity of this alloy was found to increase up to the addition of 0.7 wt.% of Cu beyond which a decrease in the electrical resistivity was observed. A change in the microstructure of the solder alloy was observed when it was reheated above the melting temperature.