U. Anwar^a, N. A. Noor^b, S. Mumtaz^c,*, I. M. Moussad¹

Chalcogenide Letters, Vol.22, No.3, pp. 261-276, 2025, DOI:10.15251/CL.2025.223.261

Abstract The combination of two-step synthesis processes is employed for the fabrication of (NiO)(_0.5)/(Fe₂O₃)(_0.5)@C@MoS₂ (NFCM) nanofibers composite through electrospinning and hydrothermal techniques. This nanofiber composite is designed for tunable dielectric materials and electromagnetic interference (EMI) shielding applications. Using impedance spectroscopy, the electrical properties of an NFCM pellet are analyzed using an equivalent circuit model (R₁1<), with a primary focus on the variation of relaxation time with frequency at different temperatures. Utilizing the Mott. variable range hopping (MVRH) model, and small polaronic hopping model, the localization length of the hoping carriers is determined to be 0.98 Å and More >

U. Anwar^a,, M. Rafi^b, N. A. Noor^c, S. Mumtaz^d,, Hosam O. Elansary^e

Chalcogenide Letters, Vol.22, No.4, pp. 293-311, 2025, DOI:10.15251/CL.2025.224.293

Abstract This study presents a multifunctional NiFe₂O₄@MoS₂ nanomaterial synthesized by co-precipitation and hydrothermal methods. The highly magnified Field emission scanning electron microscopic (FESEM) images expose an excellent interconnected network of MoS₂ petals and NiFe₂O₄ cores. NiFe₂O₄@MoS₂ nanomaterial's crystalline arrangement and phase purity are explored using X-ray diffraction (XRD) analysis. A comprehensive analysis of the NiFe₂O₄@MoS₂ nanomaterial, focusing on its dynamic electrical properties across a temperature zone of 183 K to 373 K. The temperature-dependent impedance and modulus plots versus frequency reveal insights into the material’s conduction and relaxation. Electrical characteristics verify the contribution of electroactive regions, such as grains… More >

S. Othman^a, Y. H. Lua^b, E. S. Sazali^a,, Y. S. Yap^b,, R. Hisam^c

Chalcogenide Letters, Vol.22, No.5, pp. 451-459, 2025, DOI:10.15251/CL.2025.225.451

Abstract High-performance glass-ceramics are increasingly explored for their suitability in high-frequency dielectric applications, presenting a significant challenge in materials science. A primary focus has been allocated to investigating borotellurite glasses operating at frequencies below 15 MHz. Borotellurite glasses with the composition 69TeO_₂-10B_₂O₃-10PbO-10ZnO-1Er_₂O₃ were fabricated via the melt-quenching method. This study examines the effects of heat treatment durations (1–24 hours) on these glasses. Variations in density, molar volume, structure, and dielectric properties were attributed to changes in non-bridging oxygen bonding resulting from the heat treatments. X-ray diffraction analysis confirmed the amorphous nature of the as-quenched glass. Morphological changes More >

Alan F.N. Boss¹, Manuella G.C. Munhoz¹, Gisele Amaral-Labat², Rodrigo G.A. Lima², Leonardo I. Medeiros^2,3, Nila C.F.L. Medeiros^2,3, Beatriz C.S. Fonseca², Flavia L. Braghiroli^4,*, Guilherme F.B. Lenz e Silva¹

Journal of Renewable Materials, Vol.12, No.10, pp. 1639-1659, 2024, DOI:10.32604/jrm.2024.056004 - 23 October 2024

Abstract Radar Absorbing Materials (RAM) are a class of composites that can attenuate incident electromagnetic waves to avoid radar detection. Most carbon allotropes that have the potential to be used as RAM are either carbon nanotubes (CNTs), graphene, carbon black (CB) and ultimately, sustainable porous carbon (SPC). Here, black wattle bark waste (following tannin extraction) was used as a sustainable source to produce SPC made from biomass waste. It was characterized and used as a filler for a silicone rubber matrix to produce a flexible RAM. The electromagnetic performance of this composite was compared with composites… More > Graphic Abstract

S. Mahla^a, R. Agrawal^b, S. Kumar^c, P. Singh^d, M. Lal^e, S. Singh^f, A. S. Verma^g,h,*

Chalcogenide Letters, Vol.20, No.7, pp. 535-547, 2023, DOI:10.15251/CL.2023.207.535

Abstract A subclass of ternary intermetallic known as Heusler compounds is being employed in the steel industry to increase material strength. This study examines the structural, electrical, optical, and magnetic properties of Co₂VZ (Z=Al, Bi, Ge, Si) compounds using two different methods. First is full potential linearized augmented plane wave (FP-LAPW) method by WIEN2k and second is pseudo potential method by Atomic Tool Kit-Virtual Nano-Lab. The equivalent energy gaps in the minority-spin of Co₂VZ (Z= Al, Bi, Ga, Ge) with WIEN2k code, which displays 100% spin polarization, are 0.703, 0.384, 0.186, and 0.67 eV near to the More >

Soliman Abdalla^1,2,*, Sherif Kandil², Waleed El-Shirbeeny¹, Fatma Bahabri^1,3

Journal of Renewable Materials, Vol.10, No.9, pp. 2335-2354, 2022, DOI:10.32604/jrm.2022.021211 - 30 May 2022

Abstract Diabetes disorder turns smoothly to be a global epidemic disorder and the glycated hemoglobin (HbA1c) starts to be an efficient marker of it. The dielectric spectroscopy on different human normal- and diabetic-blood samples is used to characterize and to estimate the HbA1c concentration. “dc-” and ac-measurement of the complex conductivity in the temperature range from 280 K up to 320 K, and in the frequency range from one Hz up to 32 MHz have been performed. The thermal activation energy, ΔE_σ, of dc-electric conductivity lies in the range 95 meV < ΔE_σ < 115 meV; while… More >