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5 results on '"Kakhaki, Zahra Makhdoumi"'

1. Gate-controlled supercurrent effect in dry-etched Dayem bridges of non-centrosymmetric niobium rhenium

Author

Koch, Jennifer, Cirillo, Carla, Battisti, Sebastiano, Ruf, Leon, Kakhaki, Zahra Makhdoumi, Paghi, Alessandro, Gulian, Armen, Teknowijoyo, Serafim, De Simoni, Giorgio, Giazotto, Francesco, Attanasio, Carmine, Scheer, Elke, and Di Bernardo, Angelo

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Materials Science
Abstract

The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction, named as gate-controlled supercurrent (GCS), has raised great interest for fundamental and technological reasons. To gain a deeper understanding of this effect and develop superconducting technologies based on it, the material and physical parameters crucial for GCS must be identified. Top-down fabrication protocols should be also optimized to increase device scalability, although studies suggest that top-down fabricated devices are more resilient to show GCS. Here, we investigate gated superconducting nanobridges made with a top-down fabrication process from thin films of the non-centrosymmetric superconductor NbRe. Unlike other devices previously reported, our NbRe devices systematically exhibit GCS, when made in specific conditions, which paves the way for higher device scalability. Our results also suggest that surface properties of NbRe nanobridges and their modification during fabrication are key for GCS., Comment: 14 pages, 4 figures

Published
2023
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4. Effect of Milling Energy and Process Ordering on the Morphologies and Optical Properties of ZnO Nanoparticles Obtained Through a Mechanochemical Technique.

Author

Kakhaki, Zahra Makhdoumi, Youzbashi, Amirali, and Naderi, Nima

Subjects
*NANOPARTICLES, *ELECTRO-optical effects, *OPTICAL properties, *NANOFABRICS, *BIOMACROMOLECULES
Abstract

Zinc oxide (ZnO) nanoparticles were synthesised by a mechanochemical method using ZnCl2 and Na2CO3 as precursors and NaCl as a diluent. The effects of the milling energy, influenced by factors such as the milling time and ball-to-powder mass ratio, and the ordering of the synthetic stages on the structure, morphology and optical properties of the synthesised nanoparticles were characterised by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, as well as by UVvisible and photoluminescence spectroscopies. The results indicated the direct formation of ZnO nanoparticles after 10 hours of milling, without the need for heat treatment, as a result of the high-energy milling process. The crystallite sizes of the nanoparticles increased with higher milling times and ball-to powder mass ratios due to cold welding. ZnO nanoparticles with crystallite sizes in the range of 16 nm-19 nm were produced through optimisation of the order of synthetic stages and milling energy. Different morphologies were obtained in different samples due to the effects of changing the order of the synthetic steps. The optical band gap of the synthesised ZnO nanoparticles was lower than in bulk samples because of the presence of defects. [ABSTRACT FROM AUTHOR]

Published
2015

5. Optical Properties of Zinc Oxide Nanoparticles Prepared by a One-Step Mechanochemical Synthesis Method.

Author

Kakhaki, Zahra Makhdoumi, Youzbashi, Amirali, and Naderi, Nima

Subjects
*ELECTRO-optical effects, *ZINC oxide, *NANOPARTICLES, *NANOSTRUCTURED materials, *OPTICAL properties
Abstract

ZnO nanoparticles were synthesised by a one-step mechanochemical process using ZnSO4 and NaOH as reactants with NaCl acting as a diluent. A short milling time of 30 min was required for complete reaction. The effects of oxygen vacancies and the milling time on the photocatalytic activities of the prepared nanoparticles were investigated. The structural and morphological properties of the nanoparticles were evaluated by various analytical methods, including x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The particle size of the ZnO nanoparticles without heat treatment was approximately 50 nm but was increased up to 80 nm after heat treatment at 400°C. Optical properties such as the optical band gap and the photocatalytic activity were investigated by photoluminescence and UV-vis spectroscopy, as well as by photocatalytic experiments. [ABSTRACT FROM AUTHOR]

Published
2015

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