Ateeq Ahmed

Enhanced room temperature ferromagnetism in Ni doped SnO2 nanoparticles: A comprehensive study

We emphasized on a detailed investigation of the structural, optical, and magnetic properties of pure and Ni-doped SnO2 nanoparticles (NPs) synthesized by a sol-gel process. An extensive structural study has been carried out using various characterization techniques. The X-ray Diffraction (XRD) spectra show the formation of the single phase tetragonal structure of pure and Ni-doped SnO2 NPs without any noticeable impurity phase such as NiO. XRD results indicate that the crystallite size of SnO2 is found to be decreased with Ni doping, which has also been confirmed by the Field Emission Scanning Electron Microscopy study. X-ray Photoelectron Spectroscopy (XPS) measurements displayed a clear sign for Ni2+ ions occupying the lattice sites of Sn4+ in the SnO2 host which also gives clear evidence for the formation of single phase Sn1-xNixO2 NPs. The optical analysis shows a significant decrease in the energy gap of SnO2, i.e., (from 3.71 eV to 3.28 eV) as Ni concentration increases which may be correlated with...

Structural and room temperature dielectric properties of ethylene glycol assisted pure and Al doped NiO nanoparticles

We have synthesized undoped and Al doped NiO nanoparticles with compositional formula Ni1-xAlxO (x=0 and 1%) using sol-gel method annealed at 700°C. The XRD diffraction peaks match with the pattern of the cubic structure of NiO that reveals the formation of hexagonal wurtzite structure in all samples. TEM image of undoped NiO demonstrates clearly the formation of spherical NiO nanoparticles, In addition, we have also discussed the effect of Al insertion in NiO lattice on dielectric properties such as dielectric constant, loss factor, AC conductivity and impedance Nyquist plot of our samples.We have synthesized undoped and Al doped NiO nanoparticles with compositional formula Ni1-xAlxO (x=0 and 1%) using sol-gel method annealed at 700°C. The XRD diffraction peaks match with the pattern of the cubic structure of NiO that reveals the formation of hexagonal wurtzite structure in all samples. TEM image of undoped NiO demonstrates clearly the formation of spherical NiO nanoparticles, In addition, we have also discussed the effect of Al insertion in NiO lattice on dielectric properties such as dielectric constant, loss factor, AC conductivity and impedance Nyquist plot of our samples.

Investigation of optical properties of nickel oxide nanostructures using photoluminescence and diffuse reflectance spectroscopy

Nickel oxide (NiO) nanoparticles with a crystal size of around 16.26 nm have been synthesized via sol-gel method. The synthesized precursor was calcined at 600 °C for 4 hours to obtain the nickel oxide nanoparticles. The XRD analysis result indicated that the calcined sample has a cubic structure without any impurity phases. The FTIR analysis result confirmed the formation of NiO. The NiO nanoparticle exhibited absorption band edge at 277.27 nm and the optical band gap have been estimated approximately 4.47 eV using diffuse reflectance spectroscopy and photoluminescence emission spectrum of our as-synthesized sample showed strong peak at 3.65 eV attributed to the band edge transition.Nickel oxide (NiO) nanoparticles with a crystal size of around 16.26 nm have been synthesized via sol-gel method. The synthesized precursor was calcined at 600 °C for 4 hours to obtain the nickel oxide nanoparticles. The XRD analysis result indicated that the calcined sample has a cubic structure without any impurity phases. The FTIR analysis result confirmed the formation of NiO. The NiO nanoparticle exhibited absorption band edge at 277.27 nm and the optical band gap have been estimated approximately 4.47 eV using diffuse reflectance spectroscopy and photoluminescence emission spectrum of our as-synthesized sample showed strong peak at 3.65 eV attributed to the band edge transition.

Frequency dependent dielectric properties of Sr doped NiO nanostructures

Ni1-xSrxO (x=0.0, 0.02) nanoparticles have been synthesized using sol-gel method calcined at temperature 600 °C. The XRD analysis result revealed that the calcined sample has a cubic structure with single phase structure. We have calculated crystallite size of samples using both Debye-Sherrer and William Hall (W-H) method which are found to be 19.69 nm, 22.39 nm and 28.50 nm, 33.27 nm, respectively. TEM image reveals the formation of spherical shaped particles. In addition, dielectric properties have been studied using LCR measurement and found that e′, e″ and tan δ are decreases with increase in frequency whereas ac conductivity increases with increase in frequency. This behavior may be explained using Maxwell–Wagner and Koop theory.Ni1-xSrxO (x=0.0, 0.02) nanoparticles have been synthesized using sol-gel method calcined at temperature 600 °C. The XRD analysis result revealed that the calcined sample has a cubic structure with single phase structure. We have calculated crystallite size of samples using both Debye-Sherrer and William Hall (W-H) method which are found to be 19.69 nm, 22.39 nm and 28.50 nm, 33.27 nm, respectively. TEM image reveals the formation of spherical shaped particles. In addition, dielectric properties have been studied using LCR measurement and found that e′, e″ and tan δ are decreases with increase in frequency whereas ac conductivity increases with increase in frequency. This behavior may be explained using Maxwell–Wagner and Koop theory.

Influence of Ag substitution on structural and dielectric properties of TiO2 nanoparticles

In this paper, we report the structural, electrical and dielectric properties of Ag-substituted TiO2 nanoparticles synthesized by sol-gel method. The X-ray diffraction (XRD) spectra revealed that the synthesized nanoparticles are pure and crystalline in nature and showing tetragonal anatase phase of TiO2. TEM micrograph shows that shapes of the nanoparticles are non-spherical. We have also studied the dielectric properties and in relation to it the dielectric constants, dielectric loss and A.C. conductivity have been studied as the function of frequency and composition of iron. The above theory may be explained by ‘Maxwell Wagner Model’.In this paper, we report the structural, electrical and dielectric properties of Ag-substituted TiO2 nanoparticles synthesized by sol-gel method. The X-ray diffraction (XRD) spectra revealed that the synthesized nanoparticles are pure and crystalline in nature and showing tetragonal anatase phase of TiO2. TEM micrograph shows that shapes of the nanoparticles are non-spherical. We have also studied the dielectric properties and in relation to it the dielectric constants, dielectric loss and A.C. conductivity have been studied as the function of frequency and composition of iron. The above theory may be explained by ‘Maxwell Wagner Model’.