Surface morphology and electrical properties of pulse electrodeposition of NiFe films on copper substrates in ultrasonic field

NiFe films were pulse electrodeposited on conductive copper substrates under galvanostatic mode with and without the presence of an ultrasonic field at different pulse current magnitudes and duty cycles. The optimum deposition condition was found to be at a current magnitude of 40 mA and a duty cycle of 50.00% under ultrasonic treatment. This deposition condition has significantly reduced the surface roughness from 39.01 ±1.1 nm to 6.96 ±1.1 nm and the spherical grain size in the range from 579.40 nm - 623.30 nm to 29.00 nm - 46.90 nm. On the other hand, the resistivity was reduced to 19.86 µωcm from 54.00 µωcm as the Ni content increased from 76.08% to 80.12 % for achieving good stoichiometry for NiFe thin films. Through the optimization study, the deposition current is observed to be the dominant factor in determining the single phase deposition of NiFe film whereas ultrasonic field and duty cycle significantly reduces the surface roughness and the spherical grain size, all of which combine to reduce film resistivity

Synthesis and characterization of nickel ferrite magnetic nanoparticles by co-precipitation method

Magnetic nickel ferrite (NiFe2O4) nanoparticles have been synthesized via co-precipitation method by varying the metal precursors ratio. Four different precursors ratio (Fe:Ni) are varied at 40:60, 50:50, 60:40 and 80:20. The size of the nanoparticles is found to increase with increasing iron (Fe) content. In addition, the morphology of the particles are observed to change from spherical to a shape similar to a nanooctahedral particle when the Fe content in the initial precursors ratio increases. The X-ray Diffraction (XRD) patterns have proved the presence of nickel ferrite nanoparticles. The magnetic properties characterized by Vibrating Sample Magnetometer (VSM) at room temperature proved that the assynthesized nickel ferrite nanoparticles are ferromagnetic and the saturation magnetization (Ms) increases with the content of Fe in the sample

Physical and electrical characteristics of NiFe thin films using ultrasonic assisted pulse electrodeposition

Nickel iron (NiFe) thin films were prepared on the copper substrate by ultrasonic assisted pulse electrodeposition under galvanostatic mode. Careful control of the thin films deposition is essential as the electrical properties of the films could be greatly affected, particularly if low quality films are produced. The preparation of NiFe/Cu thin films was aimed to reduce the grain size of NiFe particles, surface roughness and electrical resistivity of the copper substrates. Various parameters were systematically studied including current magnitude, deposition time and ultrasonic bath temperature. The optimized conditions to obtain NiFe permalloy, which subsequently applied to all investigated samples, were found at a current magnitude of 70 mA deposited for a duration of 2 min under ultrasonic bath temperature of 27 °C. The composition of NiFe permalloy was as close as Ni 80.71% and Fe 19.29% and the surface roughness was reduced from 12.76 nm to 2.25 nm. The films electrical resistivity was decreased nearly sevenfold from an initial value of 67.32 μΩ cm to 9.46 μΩ cm

Effects of ultrasonic field in pulse electrodeposition of NiFe film on Cu substrate.

NiFe film was pulse electrodeposited on conductive Cu substrate under galvanostatic mode in the presence of an ultrasonic field. The NiFe film electrodeposited was subjected to structural and surface analyses by X-ray diffraction, energy dispersive X-ray spectroscopy, surface profiling and scanning electron microscopy, respectively. The results show that the ultrasonic field has significantly improved the surface roughness, reduced the spherical grain size in the range from 490–575 nm to 90–150 nm, and increased the Ni content from 76.08% to 79.74% in the NiFe film electrodeposited

Surface morphology and particle size analysis of Ba0.5Sr0.5TiO3 nano-powder grown using sol-gel method

Barium Strontium Titanate powder in the form of nano cubic particles has been prepared using slow rate gellification by sol-gel method. X-Ray Diffractometer results show that single phase formation occurred at 800 °C and the crystallite size for this sample was found to be 36.06 nm. Scanning Electron Microscopy analysis shows that the particles in the sample calcinated at 800 °C do not agglomerate and the average particle size was found to be 42.30 nm. The nano particle size analyzer results show a narrow particle distribution with good uniformity

Structural and dielectric properties of iron doped barium strontium titanate for storage applications

Barium strontium titanate (BST) and iron doped barium strontium titanate (BSTF) ceramics with general formula (Ba0.5Sr0.5Ti1−yFeyO3) and different iron (Fe) contents were prepared by slow rate injection sol–gel technique. The phase analysis, morphology and dielectric properties of BSTFs were investigated. The phase analysis was carried out using XRD which revealed the crystallization of BSTF in perovskite structure with single phase. The Fe doped BST peaks shifted toward higher angles and the calculated crystallite size was 19 nm on average. The BSTF morphology was studied using TEM which showed that the particle size was affected by Fe content. The average particle size was found to be 37 nm for (Ba0.5Sr0.5Ti1−yFeyO3) with Fe concentration of (y = 0.01, 0.05 and 0.1) calcined at (600, 800 and 1000 °C). The dielectric measurements were carried out using impedance analyzer at room temperature as a function of frequency in the range of 10 Hz to 1 MHz. The dielectric constant and dielectric loss of the 1 mol% Fe-doped Ba0.5Sr0.5TiO3 at 1 kHz were 1453.69 and 0.0063, respectively. The BSTF ceramics with high dielectric constant and low dielectric loss were obtained for the application DRAM cell capacitor

Amalgamation based optical and colorimetric sensing of mercury (II) ions with silver@graphene oxide nanocomposite materials

The article describes a facile method for the preparation of a conjugate composed of silver nanoparticles and graphene oxide (Ag@GO) via chemical reduction of silver precursors in the presence of graphene oxide (GO) while sonicating the solution. The Ag@GO was characterized by X-ray photoelectron spectroscopy, X-ray powder diffraction, and energy-dispersive X-ray spectroscopy. The nanocomposite undergoes a color change from yellow to colorless in presence of Hg(II), and this effect is based on the disappearance of the localized surface plasmon resonance absorption of the AgNPs due to the formation of silver-mercury amalgam. The presence of GO, on the other hand, prevents the agglomeration of the AgNPs and enhances the stability of the nanocomposite material in solution. Hence, the probe represents a viable optical probe for the determination of mercury(II) ions in that it can be used to visually detect Hg(II) concentrations as low as 100 μM. The instrumental LOD is 338 nM

Microstructure and dielectric properties of nickel-doped Ba0.7Sr0.3TiO3 ceramics fabricated by solgel method

A study of phase transition, microstructure, and dielectric properties of Ba0.7Sr0.3Ti1–xNixO3 (BSTN) ceramics prepared by slow-injection solgel technique with x ranging from 0 to 1 mol% is reported in this article. The as-prepared BSTN material was calcined at 800 and 1000°C and subsequently sintered at 1100 and 1200°C, respectively. The optimized condition was found to be Ba0.7Sr0.3TiO3 doped with 1 mol% nickel calcined at 1000°C and sintered at 1200°C having the lowest dielectric loss of 0.02 with a dielectric constant of 1603 which was measured at a frequency of 1 kHz at room temperature

Improved dielectric performance of barium strontium titanate multilayered capacitor by means of pulsed laser deposition and slow injection sol-gel methods

A Pt/BST/NiFe/Cu multilayered capacitor was fabricated incorporating a polycrystalline Ba0.5Sr0.5TiO3 (BST) film deposited using the pulsed laser deposition technique. Qualitative X-ray diffraction analysis confirmed a perovskite structure for the deposited BST dielectric films which were fired at various temperatures. No intermediate phase was discernable with a post-annealing temperature of 750°C and highly crystallized thin film was obtained at a post-annealing temperature of 800°C. The fabricated capacitor with a BST film thickness of 665 nm exhibited respectable electrical performance with a dielectric constant, k of 657 and a dielectric loss, tan δ = 0.0137 at room temperature at an applied frequency of 1 MHz. The recorded charge storage density and leakage current density were 4.6 μC cm-2 and 33 nA cm-2, respectively, with ±5 V bias

Surface morphology of Ni-Fe thin films grown on copper substrates using pulse electrodeposition in ultrasonic field

Nickel-Iron (Ni-Fe) thin films were pulse-electrodeposited on copper (Cu) substrates under galvanostatic mode in the presence/absence of an ultrasonic field. The as-prepared thin films were characterized by X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The XRD results confirmed the deposition of NiFe on Cu substrates and the crystallite size calculated from Scherrerpsilas formula is 22.28 nm and 20.17 nm respectively for the films fabricated in the absence and presence of ultrasonic field. The grain sizes, from SEM micrographs, were found to be 225.52 nm and 79.64 nm respectively for the films fabricated in the absence and presence of ultrasonic field and the grains were in the shape of spherical balls