Alaa Alasadi
@atu.edu.iq
Tech. Institute- Karbala
RESEARCH, TEACHING, or OTHER INTERESTS
Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, General Physics and Astronomy
Scopus Publications
Scopus Publications
Ali Ghanim Gatea Al-Rubaye, Alaa Alasadi, Khalid Rmaydh Muhammed, and Catalin-Daniel Constantinescu
MDPI AG
We present a systematic study on the fabrication of gold nanoislands by microwave-assisted annealing, a rapid and energy-efficient alternative to conventional thermal treatments. Gold thin films with nominal thicknesses of 4, 5, 6, 8, and 10 nm are deposited by thermal evaporation directly onto BK7 glass substrates, with and without a 3 nm chromium adhesion layer. The samples are subsequently annealed in a microwave kiln, where microwave irradiation is absorbed and converted to heat within the graphite-coated cavity (kiln), allowing the substrate temperature to exceed 550 °C, the threshold required for film dewetting. This process induces a controlled morphological evolution from continuous thin films to well-defined nanoislands, with the final size distribution strongly dependent on the initial film thickness. Compared with oven-based annealing, microwave treatment promotes faster and more uniform heating, which enhances atomic diffusion and accelerates dewetting while reducing the risk of substrate deformation or excessive coalescence. The resulting nanoislands exhibit tailored size-dependent plasmonic properties, with clear correlations between film thickness, crystallite size, and optical absorption features. Importantly, the method is cost-efficient, requiring shorter processing times and lower energy input, while enabling reproducible fabrication of high-quality plasmonic nanostructures on inexpensive glass substrates, suitable for applications in sensing, photonics, and nanophotonics.
Waleed K. Abdulkadhim, Alaa Alasadi, Ali Ghanim Gatea AL Rubaye, Salim Albukhaty, Uday M. Nayef, and Majid S. Jabir
Springer Science and Business Media LLC
Waleed K. Abdulkadhim, Mahdi A. Mohammed, and Alaa Alasadi
Elsevier BV
Alaa Alasadi and Ghaiath A. Fadhil
AIP Publishing
Alaa Alasadi and Ali Ghanim Gatea Al Rubaye
The Materials Research Society of Korea
Alaa Alasadi, F. Claeyssens, and D. A. Allwood
IEEE Transactions on Magnetics Institute of Electrical and Electronics Engineers (IEEE)
Alaa Alasadi
Journal of Physics: Conference Series IOP Publishing
The abilities of laser direct writing have been explored on thin films of permalloy (Ni81Fe19) for range of film thicknesses with two types of substrates for creating micro-scale magnetic structures. The thin films of Permalloy were deposited on both silicon and glass substrates using thermal evaporator with ranging from 5 to 100 nm. The permalloy films were successively patterned using a laser system containing of a pico-second pulsed laser with an 800 ps pulse width and wavelength of 532 nm. A series of magnetic wires were patterned then characterised by Magneto-Optic Kerr Effect system and Scanning Electron Microscopy. The patterned magnetic wires showed good responses to an applied magnetic field. The corresponding coercivities of the patterned magnetic wires were affected by their observed quality. These results can improve the understanding of laser direct writing technique to fabricate the micromagnetic structures for future application as easy, low cost and high throughput technique.
Alaa Alasadi, F. Claeyssens, and D. A. Allwood
AIP Publishing
Laser direct writing (LDW) has been used to pattern 90nm thick permalloy (Ni81Fe19) into 1-D and 2-D microstructures with strong shape anisotropy. Sub-nanosecond laser pulses were focused with a 0.75 NA lens to a 1.85μm diameter spot, to achieve a fluence of approximately 350 mJ.cm-2 and ablate the permalloy film. Computer-controlled sample scanning then allowed structures to be defined. Scan speeds were controlled to give 30% overlap between successive laser pulses and reduce the extent of width modulation in the final structures. Continuous magnetic wires that adjoined the rest of the film were fabricated with widths from 650 nm - 6.75μm and magneto-optical measurements showed coercivity reducing across this width range from 47 Oe to 11 Oe. Attempts to fabricate wires narrower than 650nm resulted in discontinuities in the wires and a marked decrease in coercivity. This approach is extremely rapid and was carried out in air, at room temperature and with no chemical processing. The 6-kHz laser pulse repetition rate allowed wire arrays across an area of 4 mm x 0.18 mm to be patterned in 85 s.Laser direct writing (LDW) has been used to pattern 90nm thick permalloy (Ni81Fe19) into 1-D and 2-D microstructures with strong shape anisotropy. Sub-nanosecond laser pulses were focused with a 0.75 NA lens to a 1.85μm diameter spot, to achieve a fluence of approximately 350 mJ.cm-2 and ablate the permalloy film. Computer-controlled sample scanning then allowed structures to be defined. Scan speeds were controlled to give 30% overlap between successive laser pulses and reduce the extent of width modulation in the final structures. Continuous magnetic wires that adjoined the rest of the film were fabricated with widths from 650 nm - 6.75μm and magneto-optical measurements showed coercivity reducing across this width range from 47 Oe to 11 Oe. Attempts to fabricate wires narrower than 650nm resulted in discontinuities in the wires and a marked decrease in coercivity. This approach is extremely rapid and was carried out in air, at room temperature and with no chemical processing. The 6-kHz laser pulse repet...
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Tech. Institute- Karbala