Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userCatalytic effect of plasma in lowering the reduction temperature of $Fe_{2}O_{3}$
54
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Atmospheric pressure plasma (APP) generates highly reactive species that are useful for surface activations. We demonstrate a fast regeneration of iron oxides, that are popular catalysts in various industrial processes, using microwave-driven argon APP under ambient condition. The surface treatment of hematite powder by the APP with a small portion of hydrogen (0.5%) lowers the oxides reduction temperature. A near-infrared laser is used for localized heating to control the surface temperature. Controlled experiments without plasma confirm the catalytic effect of the plasma. Raman, XRD, SEM, and XPS analyses show that the plasma treatment changed the chemical state of the hematite to that of magnetite without sintering.
rate research
Read More
The work functions of (001) and (00 -1) surfaces of {alpha}-Fe_{2}O_{3} are investigated with density functional theory and symmetry slab model. These two surfaces are found to be almost nonpolarized and their work functions are 6.10 eV and 5.49 eV respectively.
We report the observation of magnetic-field-induced suppression of the spin Peltier effect (SPE) in a junction of a paramagnetic metal Pt and a ferrimagnetic insulator ${rm Y_{3}Fe_{5}O_{12}}$ (YIG) at room temperature. For driving the SPE, spin currents are generated via the spin Hall effect from applied charge currents in the Pt layer, and injected into the adjacent thick YIG film. The resultant temperature modulation is detected by a commonly-used thermocouple attached to the Pt/YIG junction. The output of the thermocouple shows sign reversal when the magnetization is reversed and linearly increases with the applied current, demonstrating the detection of the SPE signal. We found that the SPE signal decreases with the magnetic field. The observed suppression rate was found to be comparable to that of the spin Seebeck effect (SSE), suggesting the dominant and similar contribution of the low-energy magnons in the SPE as in the SSE.
We use a mapping of the multiband Hubbard model for $CuO_{3}$ chains in $RBa_{2}Cu_{3}0_{6+x}$ (R=Y or a rare earth) onto a $t-J$ model and the description of the charge dynamics of the latter in terms pf s spinless model, to study the electronic structure of the chains. We briefly review results for the optical conductivity and we calculate the quantum phase diagram of quarter filled chains including Coulomb repulsion up to that between next-nearest-neighbor $Cu$ atoms $V_{2}$, using the resulting effective Hamiltonian, mapped onto an XXZ chain, and the method of crossing of excitation spectra. The method gives accurate results for the boundaries of the metallic phase in this case. The inclusion of $V_{2}$ greatly enhances the region of metallic behavior of the chains.
Recently, materials exhibiting colossal dielectric constant ($CDC$) have attracted significant attention because of their high dielectric constant and potential applications in electronic devices, such as high dielectric capacitors, capacitor sensors, random access memories and so on.
$mathrm{beta}$-Gallium oxide ($mathrm{betambox{-}Ga_{2}O_{3}}$) is an emerging widebandgap semiconductor for potential application in power and RF electronics applications. Initial theoretical calculation on a 2-dimensional electron gas (2DEG) in $mathrm{betambox{-}(Al_{x}Ga_{1-x})_{2}O_{3}/Ga_{2}O_{3}}$ heterostructures show the promise for high speed transistors. However, the experimental results do not get close to the predicted mobility values. In this work, We perform more comprehensive calculations to study the low field 2DEG transport properties in the $mathrm{betambox{-}(Al_{x}Ga_{1-x})_{2}O_{3}/Ga_{2}O_{3}}$ heterostructure. A self-consistent Poisson-Schrodinger simulation of heterostructure is used to obtain the subband energies and wavefunctions. The electronic structure, assuming confinement in a particular direction, and the phonon dispersion is calculated based on first principle methods under DFT and DFPT framework. Phonon confinement is not considered for the sake of simplicity. The different scattering mechanisms that are included in the calculation are phonon (polar and non-polar), remote impurity, alloy and interface-roughness. We include the full dynamic screening polar optical phonon screening. We report the temperature dependent low-field electron mobility.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
