Yazar "Hamdy, Mohamed S." seçeneğine göre listele

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    First principles computation of exchange mechanism, radiation shielding, and physical properties of FeCu2SnX4(X=S, Se, Te): Transitions metal based chalcogenides for spintronic and energy storage system applications
    (Elsevier Ltd., 2025) Sohail, Shahzad; İrfan, Muhammad; Ain, Quratul; İbrahim, Fatma A.; Hamdy, Mohamed S.; Zakaly, Hesham M.H.
    This study explores the multifunctional properties of Cu-based FeCu2SnX4(X = S, Se, Te) through density functional theory (DFT) calculations, focusing on their ferromagnetic stability, optical behavior, and thermoelectric performance. Phonon dispersions and negative formation energy values validated the stability of the ferromagnetic phase of all the investigated spinels. Band structure analysis confirmed semiconducting characteristics for both spin channels, while exchange splitting energies obtained from the density of states (DOS) were used to calculate exchange constants (N0α and N0β). The strong p-d hybridization, reflected in higher N0β = −0.14, −0.18, and −0.16 and N0α = 0.11, 0.29, and 0.35, indicated that the exchange field dominates the crystal field, driving ferromagnetism. Furthermore, p-d hybridization adjusted magnetic moments at Cu and Fe sites, showcasing tunable magnetic properties. Optical analysis in the 0–6 eV photon energy range revealed low light dispersion and refractive indices of 1–2 eV within the visible spectrum, suggesting potential for optoelectronic applications. Thermoelectric studies at 500 K demonstrated positive Seebeck coefficients for FeCu₂SnS₄ and FeCu₂SnSe₄, while FeCu₂SnTe₄ showed negative coefficients at room temperature. Power factors increased with temperature from X = S to Te, highlighting their potential for thermoelectric power generation. Furthermore, the radiation shielding assessment emphasized that FeCu2SnTe4 provides an HVL of a minimum of 0.18 cm at 0.015 MeV, which clearly explains gamma-ray absorption more than other samples. This information places FeCu₂SnX₄ spinel structures as potential candidates for applications that require combined magnetic, optical, radiation shielding, and energy functionalities. These findings position FeCu₂SnX₄ spinels as promising materials for integrated magnetic, optical, radiation shielding, and energy applications. © 2025 Elsevier Ltd
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    First principles investigations of linear and nonlinear optical, radiation shielding and thermoelectric properties of the non-centrosymmetric Ba-based chalcogenides Ba2In2X5 (X=S, Te)
    (Elsevier Ltd., 2025) İrfan, Muhammad; İbrahim, Fatma A.; Hamdy, Mohamed S.; Issa, Shams A.M.; Zakaly, Hesham M.H.
    We explore the structural, elastic, optoelectronic, Radiation Shielding, and thermoelectric properties of Ba2In2X5 (X = S, Te) using first-principles computations and semi-classical Boltzmann Transport equations. These materials are classified as semiconductors exhibiting band gaps of 2.0 eV and 3.0 eV for both investigated NLO compounds that have more significant direct band gaps of superior optical birefringence and second-order NLO coefficients. The bonding properties have been investigated by analyzing the electron charge density (ECD) contour of the (1 0 1) crystallographic plane. It is clear from the reflectivity spectra that both compounds have a high degree of reflectivity, which could make them useful as UV and visible light shields. From 0 to 14.0 eV, the approximated reflectivity values, R (ω), are displayed against the incident photon energy. Therefore, the reflectivity is around 30 % before E ≈ 12.0 eV and 40 % reflection at ∼13.0 eV. Phase matching is possible for both compounds detected, as shown by the birefringence computations. Furthermore, the radiation shielding properties of Ba2In2S5 and Ba2In2Te5 have been evaluated using Phy-X software, demonstrating their potential effectiveness in medical and nuclear energy applications. The thermoelectric properties display N-type nature at low temperatures when the Seebeck coefficient changes from N to P-type at higher temperature ranges. These compounds have remarkable optical and thermal properties, rendering them highly attractive materials for thermoelectric and optoelectronic devices. © 2024 Elsevier Ltd