Browsing by Author "Prof. Dr. Muhammad Asif"

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Hydrothermal Synthesis of Nickel Doped Zinc Oxide (NixZn1-xO where x=0, 0.1, 0.2, 0.3, 0.4): Experimental and DFT Study of Structural, Electronic and Magnetic Parameters
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Usman Zakir; CIIT/SP21-RPH-011/LHR; Prof. Dr. Muhammad Asif; LHR TP 8314
Structural, electronic and magnetic properties of nickel doped zinc oxide (NixZn1-xO) are studied by employing both experimental as well as theoretical approach. Experimentally the Hydrothermal method was employed for the synthesis and different experimental characterizations were used to investigate its different properties. Theoretically we worked under the frame wok of DFT using approximations like LDA. XRD confirms the hexagonal structure of sample with lattice constant of 3.23804Å belonging to space group P63mc. FTIR spectrum revealed the absorption peak at 536 cm-1 which is due to octahedral site in the nickel doped zinc oxide. SEM was used for the investigation of surface morphology and showed the agglomeration with non- uniform particle sizes. Theoretically DFT was used and all work done using Local Density Approximation. It was revealed that LDA describes the non- magnetic structure of zinc oxide, further it can be clarified by DOS in spin up and spin down so net magnetic moment is almost zero
Nickel Substituted Manganese Oxide [NixMn1-xO, x=0.0, 0.2, 0.4]: Experimental and First Principle Study
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Muhammad Ahmad; CIIT/SP21-RPH-016/LHR; Prof. Dr. Muhammad Asif; LHR TP 8162
Experimentally the Hydrothermal method was employed for the synthesis of metal oxides [NixMn1-xO, x=0.0, 0.2, 0.4] and different experimental techniques such as X- Ray Diffraction, SEM, FTIR, Raman, and UV-vis spectroscopy were used to investigate its different properties. Theoretically we worked under the frame wok of DFT using CASTEP code and approximation LDA. XRD confirms the FCC structure of sample with lattice constant of metal oxides ranging from 4.30-4.45 Å belonging to space group fm-3m. The structural, and electronic properties of metal oxides [NixMn1- xO, x=0.0, 0.2, 0.4] are studied by employing both experimental as well as theoretical approaches. SEM analysis revealed the non-uniform distribution of particles with different sizes. FTIR spectrum revealed the absorption peak at 530-542 cm-1 which is due to octahedral sites and another absorption peak at 640-649 cm-1 is due to tetrahedral sites present in the metal oxides. Theoretically DFT was used, and all work was done in CASTEP code using local density approximations LDA, it offers accurate results with the best conformity to the experimental findings on the material's structure, band gap, and density of states.
Sheared Waveguide Analysis in Quantum Plasmas
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Muhammad Ilyas Amin; CIIT/FA17-RPH-053/LHR; Prof. Dr. Muhammad Asif; LHR TP 5732
From literature it is found that the confined plasmas particularly in cylindrical geometry is employed for the study of electrostatic waves propagating along the z-direction. However, the study of a wave in a guided channel propagating at oblique angle is still matter of interest. In this thesis we studied the electrostatic wave with sheared features in the presence of electron quantum effects like Fermi pressure, quantum tunneling and the exchange-correlation potential. The high frequency electrostatic waves have been investigated in electron plasma. These electron high frequency waves are propagating obliquely in the cylindrically bounded magnetized electron plasma. The effects of cylindrical coordinates, magnetic field and obliqueness have significant impact on these electron cyclotron frequencies. The Bessel function of zero and first order effects are observed closely. Quantum parameters are used to check the phase effect on electron cyclotron wave. These results can be helpful for understanding the laboratory plasma.
Synthesis and Investigation of Structural, Magnetic and Electronic Properties of Soft Ferrites: An Experimental and Density Functional Theory Approach
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) WASIF IRSHAD KHAN; CIIT/ FA19-RPH-018/LHR; Prof. Dr. Muhammad Asif; LHR TP 7673
The structural, electronic and magnetic properties of nickel ferrite (NiFe2O4) are studied by employing both experimental as well as theoretical approach. Experimentally the sol- gel method was employed for the synthesis and different experimental characterizations such as XRD, FTIR, SEM and VSM were used to investigate its different properties. Theoretically we worked under the frame wok of DFT using CASTEP code and some approximations like LDA, LSDA and GGA. XRD confirms the fcc structure of sample with lattice constant of 8.20 Å belonging to space group fd-3m. FTIR spectrum revealed the absorption peak at 598 cm -1 which is due to octahedral site in the inverse spinal NiFe2O4. SEM was used for the investigation of surface morphology and showed the agglomeration with non-uniform particle sizes. The magnetic properties are derived from M-H loop using VSM which confirm the soft magnetic nature of the NFO with magnetic moment 2.63 . Theoretically DFT was used and all work done in CASTEP code using different approximations. It was revealed that LSDA failed to describe the magnetic structure of the present compound, that‘s why we move forward to use GGA which provide reliable results with best agreement with the experimental results like lattice parameters, Band gap, electronic and the magnetic properties
Synthesis and Simulation of Hafnium Oxide based Nanomaterials
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Rafi Ur Rahman; CIIT/SP20-RPH-023/LHR; Prof. Dr. Muhammad Asif; LHR TP 7689
Hafnium oxide (HfO2) has a wide range of applications including optical coatings, DRAM capacitors, and solar cell devices due to high melting point and wide energy bandgap (5.3- 5.7) eV. In this project, HfO2 based nanomaterials were synthesized by using a hydrothermal method. The synthesized HfO2 nanomaterials were characterized by using several techniques including X-rays diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) analysis. X-ray diffraction (XRD) analysis was used to study the structure of Hafnium Oxide whereas FTIR analysis was used to study the functional groups in HfO2 Nanomaterials. ATLAS Silvaco was used to simulate the tunneling Oxide Passivated Contact (TOPCON) solar cell device results for passivation layers of SiO2 and HfO2. Recently, HfO2 is proposed as a passivation material for solar cell applications