Archives January 2025

Congratulation for our new paper in SREP

Magnetic nanoparticles of
Nd2Fe14B prepared by ethanol assisted wet ball milling technique
Younes Mehrifar, Hamed Moqtaderi, Seyedeh Mehri Hamidi, FaridehGolbabaei, Mahdi Hasanzadeh & Somayeh Farhang Dehghan

The magnetic material Nd2Fe14B is one of the strongest magnetic materials found in nature. The
demand for the production of these nanoparticles is significantly high due to their exceptional
properties. The aim of the present study is to synthesize magnetic nanoparticles of Nd2Fe14B using
ethanol in the wet ball milling technique (WBMT). Nd2Fe14B powder an average particle size(APS)
of 730 nm was subjected to wet ball milling in stainless steel cup containing 5 mm diameter steel
balls.The powder was milled for 12 h at 400 rpm, with intervals of 15 min and a 15-second pause
each time. The morphology of the powder and nanoparticles, crystallinity, changes of the samples
under temperature, magnetic properties, and the structural bonds were analyzed using field
emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermogravimetric analysis
(TGA), vibrating sample magnetometry (VSM), and Fourier-transform infrared spectroscopy (FTIR).
The microstructural images revealed that the shape of the particles changed from flat(730 nm) to
spherical(76 nm) after WBMT. The crystallinity results indicated a hexagonal crystal structure, with the
average crystallite size being 17.1 nm. In the spectrum of the synthesized Nd2Fe14B nanoparticles,
a peak appeared at a wavenumber of 803 cm−1, along with peaks at wavenumbers of 1037 cm−1 and
1083 cm−1, which are associated with the stretching vibrations of Nd-Fe, Fe-B, and Nd-B bonds,
respectively. Numerical results of magnetic performance parameters indicated the ferromagnetic
properties of the particles(HC=6097.47, Mr=34.65 and MS=49.11).It appears that in WBMT, the
operational parameters significantly affect the average crystallite size, saturation magnetization, as
well as the size and shape of the nanoparticles. Additionally, the ferromagnetic nature of Nd2Fe14B in
the hysteresis loop plays an important role in the thermal stability of the nanoparticles.

Congratulations for our new paper in sensors and actuators A

Magneto-plasmonic response of nickel nano-rings prepared by
electroless method

Akram Poursharif, Peyman Sahebsar, Seyyed Mahmood Monirvaghefi, Seyedeh Mehri Hamidi, Mahshid Kharaziha, Masih Bagheri

Over recent years, there has been increasing interest in the development of magneto-plasmonic nanostructures for advanced sensing applications, many of which have been produced using various lithography and sputtering deposition techniques. This research examines the magneto-plasmonic properties of nickel nano-rings with diameters between 200 and 600 nm, aimed at applications in sensing technologies. Nickel-silver-boron (Ni-Ag-B) nanoarrays were fabricated on ITO substrates through a combination of nano-sphere lithography and selective electroless deposition in a Ni-B and silver nanoparticle bath. Compared to conventional methods, this fabrication process is simpler, more cost-efficient, and produces durable coatings due to the formation of strong covalent bonds. Additionally, the electroless method generally leads to the formation of uniform coatings on complex surfaces. The distinct shape of the nano-rings enhances plasmonic effects by generating a highly concentrated electromagnetic field, outperforming other nanostructures. Unlike thin films, light reflectivity tests showed that the nano-rings exhibited surface plasmon resonance (SPR) in the 470-614 nm range at a 45° incident angle. In the next step, ellipsometry parameters were calculated. To further investigate the nano-rings’ effect, focus on the effective ellipsometry parameters. Additionally, Magneto-Optical Kerr Effect (MOKE) measurements revealed narrow Full Width at Half Maximum (FWHM) peaks at 512 nm and 560 nm, demonstrating their strong potential for highly sensitive detection compared to conventional SPR and ellipsometry-SPR. Finite element simulations using COMSOL further explored how magnetic fields influence the electromagnetic response of the nickel nano-rings, revealing promising applications in optical communication and sensing technologies.

Congratulation for our new paper in JTAP

Temperature effects on the conversion coupling efficiency in dye based Plasmonic Random Laser gain media

Mariam Kadhim Jawad, J. M. Jassim, S. F. Haddawi, S. M. Hamidi

The impact of temperature on the conversion coupling efficiency between Rhodamine 6G (Rh6G) dye and hybrid nanoparticles, composed of gold (Au) and copper (Cu), and its influence on the performance of random lasers is investigated. The study focused on the interaction between the photophysical properties of Rh6G dye molecules and the plasmonic and thermal effects of Au/Cu nanoparticles (NPs) at varying temperatures. We analyzed the interaction between the dye molecules and nanoparticles as a function of pumping energy and temperature focusing on laser parameters laser threshold, full width at half maximum (FWHM), and peak intensity. Our results show that increasing pumping energy and temperature significantly affects the FWHM’s narrowing, and peak intensity enhancement. We found that with increasing pumping energy, the FWHM narrowed to about 8 nm for Au and Cu nanoparticles, and the peak intensity was enhanced to about 40,000 a.u. for AuNPs and 28,000 a.u. for CuNPs. While, we found that with increasing temperature, the FWHM decreased to about 0.6 nm for AuNPs and 0.8 nm for CuNPs, and the peak intensity increased to about 5400 a.u. for AuNPs and 9400 a.u. for CuNPs. This study provides insight into optimizing random laser performance through temperature control, potentially advancing the development of tunable photonic devices.

congratulation for our new paper

Chitosan-C₃N₄-Plasmonic Nanocomposite as a Generation of Scatterer Points for Random Laser Application

S.F. Haddawi^, Amir Reza Sadrolhosseini, R.A. Ejbarah, S. M. Hamidi,  Mahmood Kazemzad

The random laser is a unique optical device based on multi-light scattering, and the scatterer point was used to provide the reflection mechanism. Therefore, selecting the scatterer points is significant in designing the random laser. In this study, plasmonic (gold nanoparticles and silver nanoparticles) chitosan -C₃N₄ nanocomposites were prepared using a laser ablation technique. The prepared samples have been characterized using analytical methods. So, the chitosan-C₃N₄– gold nanoparticles and chitosan-C₃N₄-silver nanoparticles have formed with a particle size of about 24 nm. The experiment confirmed the chitosan-C₃N₄– gold nanoparticles are suitable for random laser and the threshold is higher than other chitosan-C₃N₄– silver nanoparticles and chitosan-C₃N₄ nanocomposites.