Browsing by Author "Dr. Mukhtar Ahmed"

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    Exploring the Effects of Graphene Oxide Additives on Ag/NiFe2O4 Nanocomposites for Energy Storage Devices
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025-07-25) Fatima Muhammad; CIIT/FA23-RPH-015/LHR; Dr. Mukhtar Ahmed; LHR TP 9846
    This study examines the production and characterization of Ag/NiFe₂O₄ nanocomposites enhanced with Graphene Oxide (GO) to improve their energy storage ability. X-ray diffraction (XRD) indicates the creation of a spinel NiFe₂O₄ structure with notable crystallographic planes (311), (220), and (440). The sharpness and intensity of the peaks imply strong crystallinity, whereas other characteristics corroborate the presence of Ag and GO. Raman spectroscopy confirms these findings by displaying specific vibrational modes. The spectra show expanded D and G bands in the GO-doped samples, indicating excellent integration of Graphene Oxide and improved structural disorder, which leads to greater electron mobility. Pure NiFe₂O₄, Ag-doped, and GO-incorporated samples show substantial differences, emphasizing GO's synergistic role in improving structural and electrical characterization. UV-Visible spectroscopy reveals a considerable decrease in band gap energy from 1.43 eV (pure NiFe₂O₄) to 0.237 eV (Ag/NiFe₂O₄), with a little rise to 0.264 eV with GO addition. The tunability of the band gap suggests increased conductivity and photo response, both of which are the desired characteristics for electrode materials in supercapacitors and other energy Storage Devices. Adding GO to Ag/NiFe₂O₄ nanocomposites increases crystallinity, structural flaws, and optical and electrical characteristics. These enhancements establish the composite as a promising contender for next-generation energy storage systems.
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    Investigation of Manganese-Magnesium Ferrites and Nickel Oxide Composites Synthesized via Hydrothermal Method
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Saleeha Idrees Alvi; CIIT/FA23-RPH-035/LHR; Dr. Mukhtar Ahmed; LHR TP 9861
    Hydrothermal Method ,Chemical synthesis of Mn₀.₃Mg₀.₇Fe₂O₄/NiO nanocomposites for groundwater fluoride reduction using hydrothermal technique. Manganese chloride (MnCl₂), magnesium chloride (MgCl₂), ferric chloride (FeCl₃), and nickel chloride (NiCl₂) were reacted with sodium hydroxide (NaOH) to produce the nanocomposites. Because of their capacity to create stable spinel ferrite structures and support improved fluoride adsorption, these precursors were chosen. Several characterization approaches were used to assess the synthesized materials' performance and characteristics. The production of crystalline spinel ferrite and NiO phases with average crystallite sizes in the nanometer range was verified by X-ray diffraction (XRD).Scanning Electron Microscopy (SEM) showed spherical nanoparticles with uniform shape. Strong absorption was detected in the visible range by ultraviolet-visible (UV-Vis) spectroscopy, suggesting appropriate optical characteristics and enabling the band gap energy to be estimated. By detecting the distinctive vibrational modes of spinel ferrite and NiO, Raman spectroscopy provided additional confirmation of their creation, bolstering the structural and phase purity of the produced nanomaterials. As a promising, magnetically recoverable, and reusable material for sustainable water filtration, the Mn₀.₃Mg₀.₇Fe₂O₄/NiO composite showed remarkable fluoride removal effectiveness (>90%) under ideal pH circumstances.
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    Synthesis of Al-substituted BiFeO3 powders and investigation of their properties
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) RIZWAN ALI; CIIT/FA14-RPH-013/LHR; Dr. Mukhtar Ahmed; LHR TP 5706
    It is renowned that electricity and magnetism are internally combined, and their coupling was given by the four Maxwell-equations. Although the basic idea related to the crystals may well be at the same time ferromagnetism (FM) and ferroelectricity (FE) was possible offered by Pierre Curie within the 19th century however the real starting of that started in [1] during the volume of their Course of theoretical Physics. However the true modified one at an equivalent time [2] time reverse homogenous for Cr2O3 and Astrov through confirmed via an experiment [3] the same kinds of requirement within the identical substances at the mid of nineteen century. By the way Cr2O3 is to bad for the utilization as in this material antiferromagnetism its coupled with paraelectricity. Afterwards, the attempts to combine FM and FE characteristics begin in one material mainly the Soviet Union two group: the group from St.Petersburg [4, 5] and other is from Moscow [6]. After that, generally, there was no progress during this time in this area of research. The word multiferroic earlier used by H. Schmid. As he determined FM and FE in magnesium borate material [7]. The definition that he suggest to multiferroics having single phase crystal structure which at the same time having two initial ferrite characteristics. But magnesium borate materials are found not to be good practically materials due to the magneoelectric joining at low temperature and low crystal symmetry in that materials. So soon several others multiferroics that are “Cr2O3, Ti2O3, GaFeO3 , PbFe0:5Nb0:5O3” etc are exist in nature [8, 9] or can be prepared. A great interest in these field begining the study towards an main perovskite material Bismuth ferrite (BiFeO3) [5]. However, ceramic BiFeO3 was found to be conductive and the production of single phase BiFeO3 is very though task and to be used in so many device. The presence of oxygen vacancies, defects or mixed external of Fe are the main cause of conductive properties in BiFeO3. Along with the experimental studies many theoretical observations were also reported asking many questions about different real microscopic mechanisms of FM and FE in BiFeO3. Therefore in the end of 1990 there is good achievement in preparation and characterization of multiferroics. Perovskites having the structure ABO3 good impact in many groups. Between all these compounds some rare earth based compounds exihbit multiferroic characteristics because of their strange structures [10, 11]. Some Bi based compounds like “BiFeO3” [12] and “BiMnO3” [13] exihbit ME coupling at high temperature. So many articles are written on the latest progress, physics for ME characteristics and facing tough task for ongoing technology