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Ni0.7−xZn0.3MgxFe2O4 spinel ferrite nanoparticles were synthesized via self-combustion. Structural, morphological, elastic, optical, and photoluminescence properties were examined using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), selected area electron diffraction (SAED) pattern, Ultraviolet–Visible (UV–Vis) and Photoluminescence (PL) spectroscopy. XRD confirmed a cubic lattice with a preferred (311) orientation. Increasing Mg2+ ion concentration enhanced lattice parameters due to its larger ionic radius compared to Ni2+. Crystallite sizes were analyzed using Debye-Scherrer, Williamson-Hall, Halder-Wagner, and Size-Strain methods. XRD data revealed an unusual cation distribution over tetrahedral and octahedral sites. FTIR spectra confirmed the spinel ferrite structure with prominent peaks for these sites. TEM images showed spherical nanoparticles, and SAED pattern confirmed the cubic structure. Band gaps from Tauc’s plots ranged between 2.52 and 2.78 eV. PL spectra showed three sub-bands: near band edge emission, violet band, and blue band. [ABSTRACT FROM AUTHOR]

Ni0.65Zn0.35AlxFe2−xO4 that has been synthesized using a solution-gelation method and calcined at 600 °C for 4 h was characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A single-phase cubic spinel structure belonging to the Fd-3 m space group was confirmed by Rietveld refinement. The cation distribution that was anticipated using the XRD data deviated from the preferential occupancy, and the results of the magnetization analysis supported this. The two absorption bands in the FTIR spectra corresponding to the tetrahedral and octahedral sites further support the establishment of the ferrite skeleton. Al3+ doping was found to have a considerable impact on the Debye temperature, bulk modulus, and stiffness modulus measured using FTIR data. Interatomic bonding became stronger, increasing elastic moduli. The morphology was examined using SEM, whose results showed a cluster of grains. Additionally, spherical nanoparticles with an average size of 28 nm were visible in the TEM image, which is in good agreement with the crystallite size given by the Williamson-Hall method. The Mössbauer analysis and M–H data showed a soft magnetic behavior with coercivity fluctuation. According to Arrhenius plots, all samples displayed a semiconducting characteristic. With Al3+ doping, dielectric studies revealed a declining trend. [ABSTRACT FROM AUTHOR]

In the present investigation, strontium titanate nanoceramic was synthesized by incorporating iron (Fe) ion with general formula SrTi1−xFexO3 (x = 0.0, 0.1, 0.2, and 0.4) using sol-gel autocombustion method. The effect of Fe ions on the structural, morphological, electrical, dielectric, and magnetic properties of the prepared matrix has been investigated by various characterization techniques with the appropriate formulation. The structural properties such as phase space, crystallite size (D), and lattice parameter (a) of prepared matrix are calculated by X-ray diffraction (XRD) technique. The functional groups were analyzed by Fourier transform infrared spectroscopy (FT-IR). The surface morphology of the prepared nanoceramic matrix has been determined by using field emission scanning electron microscopy (FE-SEM) analysis. Calculation of average particle size and diffraction patterns was confirmed by using images from transmission electron microscopy (TEM) and selected area electron diffraction pattern (SAED), respectively. An energy dispersive spectrum analysis (EDS) confirmed the compositional stoichiometry in the investigated matrix. Electrical conductivity increased the prepared sample due to the increasing in the Fe concentration and temperature. The dielectric parameters in the frequency range of 30 Hz to 1 MHz were found higher at lower frequencies. The pure SrTiO3 matrix shows a paramagnetic nature at room temperature, but for a higher concentration of Fe doping was used to observe the weak ferromagnetic nature. Therefore, due to Fe ion concentration, the properties of the prepared matrix have been completely varied and enhancement in the magnetic properties was observed. [ABSTRACT FROM AUTHOR]

Cobalt ferrite nanoparticles were synthesized by employing chemical co-precipitation technique. The structure, morphology, elemental composition, and magnetization studies of cobalt ferrite nanoparticles were carried by XRD, FE-SEM, EDS, and VSM techniques, respectively. Rietveld refined XRD pattern exhibited the single-phase cubic spinel structure with Fd-3m space group. FE-SEM images indicated some agglomeration of spherical grains which can be attributed to high surface energy and magnetic interactions. Presence of peaks of respective elements (Co, Fe, and O) in EDS spectrum showed formation of CoFe2O4. The M–H loop recorded at 300 K revealed superparamagnetic behavior and explained by fine particles size. The blocking temperature of the CoFe2O4nanoparticles from FC-ZFC curve was found to be 144 K. Cobalt ferrite–ethylene glycol nanofluids of various concentrations 0.0–1.0% in steps of 0.2% were prepared by ultrasonically assisted two-step technique. Thermophysical parameters such as thermal conductivity, specific heat, viscosity, and density were investigated as a function of both volume fraction and temperature. The experimental and theoretical value of each sample was correlated. The thermal conductivity was significantly enhanced with an increase in volume fraction and temperature. [ABSTRACT FROM AUTHOR]

In the present study, Li0.5+0.5xTixFe2.5−1.5xO4 (where, 0.0 ≤ x ≤ 1.0 in step of 0.2) nanoparticles were synthesized via sol-gel auto combustion technique. The nanocrystalline samples exposed to 60Co gamma (γ)-radiation of 5 Mrad dose, to understand its effect on structural, morphological, electrical and dielectric properties. The nanoparticles characterized by X-ray diffraction and field emission scanning electron microscopy (FE-SEM) techniques before and after irradiation. The irradiated samples give good crystallinity, and small crystallite size (~ 25 nm) as compared to pristine samples (~ 45 nm) and the lattice parameter gets decreased up to ~ 0.01 Å. The FE-SEM images of pristine samples show spherical morphology, whereas irradiated samples showed some cracks in it. Temperature-dependent conductivity measured by two probe technique reveals that the conductivity decreases (upto ~ 5 × 10−5Ω−1) after irradiation by obeying Ohmic nature. The dielectric measurements show the strong influence of irradiation on all the samples. [ABSTRACT FROM AUTHOR]

The effect of 112 mJ Nd: YAG laser irradiation on structural, morphological, infrared and magnetic properties of Ni 1+x Zr x Fe 2–2x O 4 spinel ferrite nanoparticles has been systematically investigated in the present work. The sol-gel auto combustion synthesis method was successfully executed for the synthesis of the present system. All the samples were characterized by X-ray diffraction technique (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR) technique. The magnetic properties of the present samples were measured by pulse field hysteresis loop technique. All the properties were measured for laser irradiated samples as well, to understand the effect of irradiation on the properties. The single-phase cubic spinel structure was confirmed by X-ray diffraction patterns of all samples and the disordered structure was observed for irradiated samples. The two principle absorption bands in IR spectra also confirm the formation of the spinel structure. Spherical and agglomerated morphology was observed for Zr 4+ substituted nickel ferrite, whereas scratched morphology was observed for the irradiated samples. The grain size confirms the nanocrystalline nature, the crystallite size also evident the same. The magnetic parameters decreased after Zr 4+ ion doping and strongly influenced by the irradiation. [ABSTRACT FROM AUTHOR]