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Effect of the electrodeposition potential on the magnetic properties of FeCoNi films

Abstract

The effect of electrodeposition potential on the magnetic properties of the FeCoNi films has been reported in this paper. The FeCoNi electrodeposition was carried out from sulfate solution using potentiostatic technique. The obtained FeCoNi films were characterized by X-ray diffractometer (XRD), atomic absorption spectrometer (AAS) and vibrating sample magnetometer (VSM). It has been shown that the electrodeposition potential applied during the synthesis process determines the magnetic characteristics of FeCoNi films. The more negative potential is applied, the higher Ni content is in the FeCoNi alloy. At the same time, Co and Fe showed almost similar trend in which the content decreased with an increase in applied potential. The mean crystallite size of FeCoNi films was ranging from 11 nm to 15 nm. VSM evaluation indicated that the FeCoNi film is a ferromagnetic alloy with magnetic anisotropy. The high saturation magnetization of FeCoNi film was ranging from 86 A·m2/kg to 105 A·m2/kg. The film is a soft magnetic material which was revealed by a very low coercivity value in the range of 1.3 kA/m to 3.7 kA/m. Both the saturation magnetization and coercivity values decreased at a more negative electrodeposition potential.

Open access
Effects of Al doping on defect behaviors of ZnO thin film as a photocatalyst

Abstract

Al doped ZnO (AZO) thin films were prepared on silica substrates by sol-gel method. The films showed a hexagonal wurtzite structure with a preferred orientation along c-axis. Suitable Al doping dramatically improved the crystal quality compared to the undoped ZnO films. Dependent on the Al dopant concentration, the diffraction peak of (0 0 2) plane in XRD spectra showed at first right-shifting and then left-shifting, which was attributed to the change in defect concentration induced by the Al dopant. Photocatalytic properties of the AZO film were characterized by degradation of methyl orange (MO) under simulated solar light. The transmittance of the films was enhanced by the Al doping, and the maximum transmittance of 80 % in the visible region was observed in the sample with Al concentration of 1.5 at.% (mole fraction). The film with 1.5 at.% Al doping achieved also maximum photocatalytic activity of 68.6 % under solar light. The changes in the film parameters can be attributed to the variation in defect concentration induced by different Al doping content.

Open access
Preparation and characterization of cobalt and copper oxide nanocrystals

Abstract

Copper oxide and cobalt oxide (Co3O4, CuO) nanocrystals (NCs) have been successfully prepared using microwave irradiation. The obtained powders of the nanocrystals (NCs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and Fourier-transform infrared spectroscopy. The obtained results confirm the presence of both nanooxides which have been produced during chemical precipitation using microwave irradiation. TEM micrographs have shown that the obtained nanocrystals are characterized by high dispersion and narrow size distribution. The results of X-ray diffraction confirmed those obtained from the transmission electron microscope. Optical absorption analysis indicated the direct band gap for both kinds of the nanocrystals.

Open access
Structural analysis and dielectric relaxation mechanism of conducting polymer/volcanic basalt rock composites

Abstract

In this work, polypyrrole and polythiophene conducting polymers (CPs) have been synthesized and doped with volcanic basalt rock (VBR) in order to improve their dielectric properties for technological applications. The structure and morphology of the composites with different VBR doping concentrations were characterized by FT-IR and SEM analyses. The best charge storage ability was achieved for maximum VBR doping concentration (50.0 wt.%) for both CPs. Dielectric relaxation types of the composites were determined as non-Debye type due to non-zero absorption coefficient and observation of semicircles whose centers were below Z′ axis at the Nyquist plots. It was also ascertained that VBR doping makes the molecular orientation easier than for non-doped samples and reduced energy requirement of molecular orientation. In addition, AC conductivity was totally masked by DC conductivity for all samples at low frequency.

Open access
Tapered fiber sensor in the near infrared wavelength

Abstract

Simulated transmission spectra for tapered fibers with no taper, one taper and two tapers in the near infrared wavelength range, calculated by Finite-Difference-Time-Domain method are currently presented. Transmission peak positions tend to shift to the shorter wavelength when the taper deformation is added to the fiber or the taper width gets narrower. The thickness sensitivity for the tapered structures with different taper thicknesses is about 2.28e-3 nm·μm−1. There is an interference structure in the electric field distribution images, which reveals in the fiber structures. The transmission spectra for the fiber without taper, one taper and two-tapered structures were simulated in near infrared wavelength by FDTD. The transmission spectra for tlated in near infrared wavelength by FDTD. The sensitivity of the fiber was about 50 nm × RIU−1 and it had better refractive index detection. The tapered fiber can be applied to the bio-chemical sensors and physical deformation testing.

Open access
Investigation, analysis and comparison of current-voltage characteristics for Au/Ni/GaN Schottky structure using I-V-T simulation

Abstract

In this work, we have presented a theoretical study of Au/Ni/GaN Schottky diode based on current-voltage (I-V) measurement for temperature range of 120 K to 400 K. The electrical parameters of Au/Ni/GaN, such as barrier height (Φb), ideality factor and series resistance have been calculated employing the conventional current-voltage (I-V), Cheung and Chattopadhyay method. Also, the variation of Gaussian distribution (P (Φb)) as a function of barrier height (Φb) has been studied. Therefore, the modified ((1n(I0T2)-(q2σs022kT2)=1n(AA*)-qB0kT)vs.(1kT)) relation has been extracted from (I-V) characteristics, where the values of ΦB0 and ASiuml* have been found in different temperature ranges. The obtained results have been compared to the existing experimental data and a good agreement was found.

Open access
Studies on the growth and characterization of L-cysteine hydrogen fluoride single crystal

Abstract

L-cysteine hydrogen fluoride (LCHF) single crystals were grown from aqueous solution. Single crystal X-ray diffraction, FT-IR, UV-Vis-NIR, and TG-DTA were used to test the grown crystals. The specimen dielectric and mechanical behaviors were also studied. Powder X-ray diffraction of the grown crystal was recorded and indexed. The optical properties of the LCHF crystal were determined using UV-Vis spectroscopy. It was found that the optical band gap of LCHF was 4.8 eV. The crystal functional groups were identified using FT-IR. Second harmonic generation (SHG) efficiency of the LCHF was three times higher than that of KDP. The dielectric constant, dielectric loss and AC conductivity were measured at different frequencies and temperatures.

Open access
Enhancement of Faraday rotation in defect modes of one-dimensional magnetophotonic crystals

Abstract

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.

Open access
Vibrational, electrical, dielectric and optical properties of PVA-LiPF6 solid polymer electrolytes

Abstract

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.

Open access
Impact of g-Load Shift on Temporal Expression Pattern of Apoptosis-linked Proteins in the Rat Mammary Gland

Abstract

Alteration in gravitational load impacts homeorhetic response in rat dams which affects neonatal pup survival. However, the effects of hypergravity (HG) exposure on the abundance of apoptosis-associated proteins in mammary epithelial cells (MECs) have not been characterized. Therefore, we examined whether chronic exposure to HG from midpregnancy alters the abundance of proapoptotic proteins in MECs during the late pregnancy and early lactation. A group of pregnant Sprague Dawley rats were exposed to either HG (2g) or normo-gravity (1g: stationary control [SC]) from days 11 to 20 of gestation (G20). Another set of animals were investigated from day 11 of pregnancy through days 1 and 3 (P1 and P3, respectively) postpartum. Quantitative (pixels [px]/lobule) immunohistochemistry at G20 of Cleaved Caspase-3 (CC-3), Tumor Protein p53 (P53), and vitamin D receptor (VDR) revealed that all the three proteins were increased (p<0.01) in HG rats compared to SC animals. At P1, the HG group had twofold higher (p<0.001) expression of CC-3 relative to the SC group. Approximately, 50% (p<0.001) more VDR was detected in the HG cohorts than SC at P3. These results suggest that a shift in g-load upregulates the expression of key proapoptotic proteins during the pregnancy-to-lactation transition in the rat MECs.

Open access