Browsing by Author "Gautam, A."

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    Neodymium doped graphene quantum dots/PANI composite for supercapacitor application
    (Elsevier Ltd, 2025) Muhiuddin, M.; Bharadishettar, N.; Devi, N.A.; Gautam, A.; Chauhan, S.S.; Siddique, A.B.; Ahmad, M.I.; Satyanarayan, M.N.; K, U.B.; Akhtar, W.; Rahman, M.R.
    The publication presents a streamlined and economical technique for fabricating advanced electrode materials to enhance the energy storage capabilities of supercapacitors (SCs). The focus is on synthesizing neodymium-doped graphene quantum dots (Nd-GQDs) via a microwave-assisted hydrothermal (MAH) process. This method uses microwave irradiation's rapid heating and efficient energy transfer under low pressure and minimal reaction time. The resulting Nd-GQDs exhibit enhanced electrochemical properties, including increased capacitance and improved charge storage, making this approach practical and effective for advancing supercapacitor technology. An exceptional specific capacitance of 618 F g?1 at a 5 mV s?1 scan rate is demonstrated using Nd-GQDs as the SC electrode material. Due to their high specific capacitance, Nd-GQDs, when combined with polyaniline (PANI), improve the energy and power density of SCs. Nd-GQDs/PANI composites with varying amounts of Nd-GQDs in symmetric SCs are fabricated to demonstrate their promising properties for SC applications. SCs fabricated with 20 mL of Nd-GQDs in the PANI matrix showed a superior specific capacitance of 354 F g?1 at a current density of 1 A g?1, while the energy density and power density were 49.15 Wh kg?1 and 2000 W kg?1, respectively. © 2025 Elsevier B.V.
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    Substrate-bias driven sputter deposited ?[jls-end-space/]-phase dominated tungsten film for spintronic applications
    (Elsevier B.V., 2025) Rajawat, A.S.; Ahmad, N.; Nasril, R.; Sheikh, T.; Muhiuddin, M.; Sahu, S.; Gautam, A.; Kumar, A.; Ahmad, M.I.; Basheed, G.A.; Rahman, M.R.; Akhtar, W.
    ?[jls-end-space/]-Tungsten (?[jls-end-space/]-W), an A15 cubic phase of tungsten, exhibits a giant spin Hall angle compared to its bcc-phase ?[jls-end-space/]-Tungsten (?[jls-end-space/]-W), making high-quality ?[jls-end-space/]-W films desirable for spintronic applications. We report the controlled growth of ?[jls-end-space/]-W films on SiO2/Si substrates via DC sputtering, where substrate bias serves as a critical factor in stabilizing the ? phase by regulating the energy of deposited atoms. This approach enables the formation of ?[jls-end-space/]-W films over a wide thickness range. Power spectral density analysis of the atomic force microscopy images revealed that the ?[jls-end-space/]-W film grown at a positive substrate bias of +50 V exhibits low surface roughness along with small grain size. Additionally, we studied the spin pumping phenomena in different tungsten phases achieved through substrate bias. Ferromagnetic resonance measurements reveal an enhancement in the magnetic damping for ?[jls-end-space/]-W/Py compared to ?[jls-end-space/]-W/Py dominated film. Importantly, the use of substrate bias does not deteriorate the interface quality, underscoring its effectiveness. These findings highlight the potential of substrate bias in thin-film engineering, paving the way for its advanced utilization in spintronic applications. © 2025 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.