Browsing by Author "Dr. Salman Naeem Khan"

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    Study on Synthesis and Characterization of Gadolinium Doped Cobalt Ferrites using Sol-gel Route
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2023) Sana Talib; CIIT/SP22-RPH-021/LHR; Dr. Salman Naeem Khan; LHR TP 8784
    In this research work, Gadolinium doped cobalt ferrite (𝐶𝑜𝐹𝑒2−𝑥 𝐺𝑑𝑥𝑂4) nanoparticles were prepared by sol-gel auto-combustion method and their nano-composites with Multi-Walled Carbon Nanotubes (MWCNTs) were synthesized using ultra-sonication route. Gadolinium (𝐺𝑑) is a rare earth element and it is very important in magnetic resonance techniques because of its strong paramagnetic properties. The nano- composites were characterized through UV-visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM) and Energy Dispersive X-ray Analysis (EDX). Fourier transform infrared spectroscopy demonstrates the existence of functional groups on the surface of carbon nanotubes and the aggregation of 𝐺𝑑 doped cobalt ferrites nanoparticles on MWCNTs was seen by SEM. The absorption and the optical band gaps values are showing increasing trend with increasing doping concentration and with CNTs deposition, which is also evidencing the enhancement of magnetic behavior. The research revealed that Gadolinium doping influenced the crystal structure, magnetic behavior, and electrical conductivity of cobalt ferrite. These changes can be utilized to tailor the properties of cobalt ferrite for specific applications like tunable dielectric devices, magnetic storages devices, and sensors.
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    Synthesize and Characterization of Rare Earth Doped Ferrites
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Ahad Ali Khan; CIIT/Fa17-RPH-018/LHR; Dr. Salman Naeem Khan; LHR TP 5718
    In this study, Yttrium doped Copper ferrite (𝐶𝑢𝐹𝑒2−𝑥𝑌𝑥𝑂4; 𝑥 = 0.1, 0.2, 0.3, 0.4, 0.5) were synthesized through sol-gel auto combustion technique. X-ray diffraction and scanning electron microscope is employed to carry out structural and morphological study of as prepared samples. The XRD patterns confirms the formation copper spinel structure, with increasing concentration of dopant induces an impurity phase of YFeO3. And SEM images display the spherical like particles with decreasing tendency ~ 2.14-1.28 μm. Vibrational modes were examined through Raman and FTIR Spectra. Observed 5 Raman modes of Γ = A1g + E1g + 3T2g affirm spinel structure with M-O bonding in undoped sample while increasing Yttrium concentration shifts the modes and increases the intensity of 3T2g mode at 512.5 nm. FTIR plot the site preference of metallic ions, Cu-O vibration at 651.5 nm corresponds to tetrahedral site. Dielectric and magnetic properties were investigated through Vector Network Analyzer, range from 1-6 GHz. The decrease in real permittivity from ~ 5-3 (F/m) as well as in real permeability ~ 2.5-1.75 (H/m) by increasing Y3+ content. This trend directly correlate with degree of crystallinity. The magnetodielectric properties are suitable for use in radar systems and shielding applications.