Spintronic offers a solution by exploiting spin instead of electron charge since spin current propagation can occur in principle without dissipation. One of the applications involve within this project for storage media is heat-assisted magnetic recording (HAMR). The objective of this study is to simulate the behavior of thermal gradient to generate a pure spin current using an ultrafast femtosecond (fs) laser in a nano-sized multilayered structure of (Al2O3/Ni81Fe19 (Py)/Cu/Y3Fe5O12 (YIG)/Gd3Ga5O12 (GGG)) at room temperature. A ferromagnetic/spacer/magnetic insulator nano-sized multilayered is the proposed structure for this study. Electron spin, directed by the external applied magnetic field, is transferred via the spacer to the magnetic insulator, leading to the generation of a spin-wave within the last layer. The ultrafast laser generates a spark of spin diffusion to get spin current. The thermal behavior within the trilayer simulated using COMSOL Multiphysics (v 5.5) is presented and supported by the theoretical model. Simulation results showed the effect of thickness and time on the generated spin current. Moreover, the thickness of the permalloy layer plays an essential role in generating a high-temperature gradient within a magnetic insulator to generate a spin current.
The effect of air injection device on the performance of airlift pump used for water pumping has been studied numerically and experimentally. An airlift pump of dimensions 42mm diameter and 2200 mm length with conventional and modified air injection device was considered. A modification on conventional injection device (normal air-jacket type) was carried out by changing injection angle from 90 (for conventional) to 22.5 (for modified). Continuity and Navier-Stokes equations in turbulent regime with an appropriate two-phase flow model (VOF) and turbulent model ( ) in two dimensions axisymmetry flow were formulated and solved by using the known package FLUENT version (14.5). The numerical and experimental investiga
... Show MoreThis work presents the study of the dark current density and the capacitance for porous silicon prepared by photo-electrochemical etching for n-type silicon with laser power density of 10mw/cm2 and wavelength (650nm) under different anodization time (30,40,50,60) minute. The results obtained from this study shows different chara that different characteristic of porous diffecteristics for the different porous Silicon layers.
The applications of hot plasma are many and numerous applications require high values of the temperature of the electrons within the plasma region. Improving electron temperature values is one of the important processes for using this specification in plasma for being adopted in several modern applications such as nuclear fusion, plating operations and in industrial applications. In this work, theoretical computations were performed to enhance electron temperature under dense homogeneous plasma. The effect of power and duration time of pulsed Nd:YAG laser was studied on the heating of plasmas by inverse bremsstrahlung for several values for the electron density ratio. There results for these ca
... Show MoreCarbon nanoparticles (CNPs) formed by one-step laser ablation in deionized water were carefully studied. Scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and UV–V spectroscopy were used to obtain morphological, chemical, and optical properties of CNPs. SEM outcomes established that the synthesized nanoparticles are semi-spherical with a wide particle size distribution. Raman investigation showed two typical and expected peaks ~ (1300 - 2700) cm−1, which are confirming to transverse and longitudinal modes of the carbon structure. The absorption spectra proved that the intensity of spectra increases as particle size and concentration increase.
In this work; copper oxide films (CuO) were fabricated by PLD. The films were analyzed by UV-VIS absorption spectra and their thickness by using profilometer. Pulsed Nd:YAG laser was used for prepared CuO thin films under O2 gas environment with varying both pulse energy and annealing temperature. The optical properties of as-grown film such as optical transmittance spectrum, refractive index and energy gap has been measured experimentally and the effects of laser pulse energy and annealing temperature on it were studied. An inverse relationship between energy gap and both annealing temperature and pulse energy was observed.
The mobile services are the most important media between many of telecommunication means such as the Internet and Telephone networks, And thatis be cause of its advantage represented by the high availability and independence of physical location and time,Therefore, the need to protect the mobile information appeared against the changing and the misuse especially with the rapid and wide grow of the mobile network and its wide usage through different types of information such as messages, images and videos. The proposed system uses the watermark as tool to protect images on a mobile device by registering them on a proposed watermarking server. This server allows the owner to protect his images by using invisible wat
... Show Moren this work, it have earthquakes data been analytized as a result of ground water injection attendant to dig wells and oil, which affects the pressure pores in the rock and is according to cause a medium-sized earthquake that have already occurred more than 20 times. according to the publication of the Department of Attenba, the dangers of earthquakes and movement flooring in Guy-Greenbrie-United area of one of United States of America cities, where these data represent a monitor magnitudes of earthquakes from September 2008 the September 2011, we conducted statistical analysis and create a model for earthquakes flooring that was chosen for four dis-tributions and results i the optima reveal the best distribution is the Burr X11 then Gen
... Show MoreCu-Al-Ni shape memory alloy specimens has been fabricated using powder metallurgy technique with tube furnace and vacuum sintering environment , three range of Nb powder weight percentage (0.3,0.6,0.9)% has been added. Micro hardness and sliding wear resist has been tested followed by X-ray diffraction, scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDX) for micro structure observation. The experimental test for the samples has showed that the increase of Nb powder weight percentage in the master alloy has a significant effect on increasing the hardness and decreasing the wear resist therefore it will enhance the mechanical properties for this alloy.