B. I. Ita

Magneto-structural properties of Ni–Zn nanoferrites synthesized by the low-temperature auto-combustion method

Using nickel, zinc and ferric nitrates, and glycine in a fuel-rich composition, Ni1−x ZnxFe2O4 nanoparticles were prepared by a simple low-temperature auto-combustion method without further sintering at high temperatures. The auto-combusted powders obtained were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray (EDAX) analysis and vibrating scanning magnetometer measurements. XRD confirms the formation of pure nanocrystalline spinel phases with an average diameter of about 55 nm. Raman spectra show tetrahedral and octahedral sites in the structure of Ni1−xZnxFe2O4 and also imply the doping of Zn2+ and displacement of Fe3+ ions from the tetrahedral site. EDAX showed that the samples were close to the nominal compositions. The magnetic measurement shows that the saturation magnetization and remanence magnetization decreases with the increase in the zinc content.

Low-temperature solution-combustion synthesis and magneto-structural characterization of polycrystalline La1–xAgyMnO3 (y ≤ x) manganites

Silver is known to be a highly mobile (low-soluble) component in Ag-doped perovskite manganites and hence several non-perovskite phases can exist in silver doped manganite perovskites with most synthetic routes making its synthesis to be problematic. In search of soft synthesis route, the low temperature combustion synthesis and magneto-structural studies of polycrystalline La1–xAgyMnO3 (y ≤ x) ceramic manganites using glycine as a fuel is reported. The sintered powders were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDAX) analysis, Thermo Gravimetric Analysis (TGA) and Vibrating Scanning Magnetometer (VSM) measurements. XRD patterns showed formation of mainly single rhombohedral perovskite phase for the La0.8Ag0.15MnO3 sample and an admixture of secondary phases with La0.8Ag0.1MnO3 and La0.8Ag0.2MnO3 samples. The distinct microstructure and higher magnetic properties observed for La0.8Ag0.15MnO3 sample compared to the other samples were discussed based on the XRD results.

Experimental and theoretical studies of (E)-N′-1-(4-propylbenzylidene)nicotinohydrazide as corrosion inhibitor of mild steel in 1 M HCl

The efficiency of a novel Schiff base namely (E)-N′-1-(4-propylbenzylidene)nicotinohydrazide (PBNH) was investigated as corrosion inhibitor of mild steel (MS) in 1M HCl using weight loss technique at 303 and 313 K. It was established that corrosion rate of mild steel increases with increase in temperature and concentration of HCl. Results showed that PBNH considerably inhibited the corrosion of mild steel in a 1 M HCl solution and inhibition efficiency is about 70% at 4 × 10−4 M PBNH at both temperatures. The inhibition efficiency of PBNH increased with an increase in concentration and temperature. The adsorption model obeys the Langmuir adsorption isotherm and the kinetic-thermodynamic model and the value of free energy of adsorption, ΔGads indicated that the adsorption of PBNH was a spontaneous process and was both an electrostatic-adsorption (physisorption) and adsorption on the basis of donor-acceptor interactions (chemisorption). Thermodynamic parameters calculated show the spontaneity and endothermic nature of the process and also reveal the favourable affinity of PBNH towards the mild steel surface. Quantum chemical calculations based on PM3 method was performed on PBNH and calculated parameters gave useful information to explain the interaction between the surface of metal and PBNH.

Structural, morphological and magnetic properties of La1−xNayMnO3 (y ≤ x) nanoparticles produced by the solution combustion method

The rapid solution combustion synthesis and characterization of sodium (Na)-substituted LaMnO 3 phases at relatively low temperature using polyvinyl alcohol (PVA) as fuel were reported. The thermal decomposition process investigated by means of differential and thermal gravimetric analysis (TG–DTA) showed that the use of PVA as a fuel was satisfactory in the synthesis of the perovskite manganite compound. Structural study using X-ray diffraction showed that all the samples were single phasic without any detectable impurities within the measurement range. Also, the Na-substituted compounds crystallize with rhombohedral symmetry (space group R-3c, no. 167) with La0.80Na0.15MnO3 manganite sample giving the highest crystallinity. Microstructural features observed by field-emission scanning electron microscopy demonstrated that most of the grains were nearly spherical in shape with fairly uniform distribution and all the observed particles connect with each other. Energy-dispersive X-ray analyses confirm the homogeneity of the samples. Increase in magnetic moment was observed with the increase in sodium doping. Room-temperature vibrating sample magnetometer measurements showed that the samples were ferromagnetic with compositions y = 0.10, 0.15 and 0.20 showing relatively high magnetic moments of 33, 34 and 36 emu g−1, respectively.

Solutions of the Klein-Gordon equation with equal scalar and vector harmonic oscillator plus inverse quadratic potential

The solutions of the Klein-Gordon equation with equal scalar and vector harmonic oscillator plus inverse quadratic potential for S-waves have been presented using the Nikiforov-Uvarov method. The bound state energy eigenvalues and the corresponding un-normalized eigenfunctions are obtained in terms of the Laguerre polynomials.

Silica Functionalized Magnesium Ferrite Nanocomposites for Potential Biomedical Applications: Preparation, Characterization and Enhanced Colloidal Stability Studies

Magnetic nanocomposite material composed of silica coated MgFe2O4 for potential biomedical applications were synthesized by a two-step chemical method including solution combustion synthesis, followed by silica coatings of the ferrite nanoparticles. The effects of silica coatings on the structural, morphological and magnetic properties were comprehensively investigated using powder X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), energy dispersive absorption x-ray (EDAX), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TG–DTA) and vibrating sample magnetometer (VSM). The colloidal behaviour of coated MNPs in physiological saline medium like water or phosphate buffer saline (PBS) was also studied by zeta potential measurements. The XRD patterns indicate that the crystalline structure is single cubic spinel phase and the spinel structure is retained after silica coating. Also, after silica coating, the crystallite size (from Scherrer formula) decreases from 53 to 47 nm. The magnetic results show that MgFe2O4 MNPs (bare and silica coated) is ferrimagnetic at room temperature. Zeta potential studies revealed that there is enhanced colloidal stability of MgFe2O4 MNPs after silica coating in aqueous media which is an applicable potential in biomedical applications.

Synthesis, Magneto-structural Properties and Colloidal Stability Studies of Ni0.3Zn0.7Fe2O4 Nanoparticles Coated with Pluronic P123 Block Copolymer for Potential Biomedical Applications

Spinel Ni0.3Zn0.7Fe2O4 (NZFO) magnetic nanoparticles was prepared by the low temperature auto-combustion method using a glycine fuel-rich composition without any further heat treatment at high temperature. Subsequently, the synthesized MNPs were coated with Pluronic P123 (PP123) after its surface was functionalized with oleic acid (OA). The effect of the coatings on the morphology, structural and magnetic properties of NZFO nanoparticles was studied using powder X-ray diffraction (XRD), Fourier transform infrared, thermogravimetric analysis, field emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM). The colloidal behaviour of coated MNPs in physiological saline medium like water or phosphate buffer saline (PBS) was also studied by zeta potential measurements. XRD results showed the formation of cubic spinel crystalline phase with and without OA–PP123 coatings. Also, after OA–PP123 coating, the crystallite size (from Scherrer formula) decreases from 55 to 53 nm. However, an enlargement in the particle size and a reduction in agglomeration were observed from FE-SEM results when the nanoparticles were coated with OA–PP123. VSM measurements showed ferromagnetic behaviour at room temperature before and after coating. The colloidal stability study of the coated sample revealed a considerable high zeta potential value at physiological pH (7.4) highlighting its potential biomedical applications.

Solutions of the Schrödinger equation with inversely quadratic effective plus Mie-type potential using Nikiforov-Uvarov method

The Schrodinger equation with the interaction of inversely quadratic effective and Mie-type potential has been solved for any angular momentum quantum number l using the Nikiforov-Uvarov method. The bound state energy eigenvalues and the corresponding un-normalized eigenfunctions are obtained in terms of the Laguerre polynomials. Several cases of the potential are also considered and their eigen values obtained.

Solutions of the Schrödinger equation with inversely quadratic Hellmann plus inversely quadratic potential using Nikiforov-Uvarov method

By using the Nikiforov-Uvarov (NU) method, the Schrodinger equation has been solved for the interaction of inversely quadratic Hellmann (IQHP) and inversely quadratic potential (IQP) for any angular momentum quantum number, l. The energy eigenvalues and their corresponding eigenfunctions have been obtained in terms of Laguerre polynomials. Special cases of the sum of these potentials have been considered and their energy eigenvalues also obtained.