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Spinel ferrite Ni 0. 0 8 Mn 0. 9 0 Zn 0. 0 2 Fe2O4 was prepared by a conventional ceramic process followed by sintering at three different temperatures (1050 ∘ C, 1100 ∘ C and 1150 ∘ C). X-ray diffraction (XRD) investigations stated the single-phase cubic spinel structure and the FTIR spectra revealed two prominent bands within the wavenumber region from 600 cm − 1 to 400 cm − 1 . Surface morphology showed highly crystalline grain development with sizes ranging from 0.27 μ m to 0.88 μ m. The magnetic hysteresis curve at ambient temperature revealed a significant effect of sintering temperature on both coercivity ( H c) and saturation magnetization ( M s). Temperature caused a decrease in DC electrical resistivity, while the electron transport increased, suggesting the semiconducting nature of all samples and that they well followed the Arrhenius law from which their activation energies were determined. The values of Curie temperature ( T c) and activation energy were influenced by the sintering temperature. Frequency-dependent dielectric behavior (100 Hz–1 MHz) was also analyzed, which may be interpreted by the Maxwell–Wagner-type polarization. The UV–vis–NIR reflectance curve was analyzed to calculate the bandgap of ferrites, which showed a decreasing trend with increasing sintering temperature. [ABSTRACT FROM AUTHOR]

Spinel ferrite [Formula: see text][Formula: see text][Formula: see text]Fe2O4 was prepared by a conventional ceramic process followed by sintering at three different temperatures (1050[Formula: see text] C, 1100[Formula: see text] C and 1150[Formula: see text] C). X-ray diffraction (XRD) investigations stated the single-phase cubic spinel structure and the FTIR spectra revealed two prominent bands within the wavenumber region from 600 cm[Formula: see text] to 400 cm[Formula: see text]. Surface morphology showed highly crystalline grain development with sizes ranging from 0.27 [Formula: see text]m to 0.88 [Formula: see text]m. The magnetic hysteresis curve at ambient temperature revealed a significant effect of sintering temperature on both coercivity ([Formula: see text] and saturation magnetization ([Formula: see text]. Temperature caused a decrease in DC electrical resistivity, while the electron transport increased, suggesting the semiconducting nature of all samples and that they well followed the Arrhenius law from which their activation energies were determined. The values of Curie temperature ([Formula: see text] and activation energy were influenced by the sintering temperature. Frequency-dependent dielectric behavior (100 Hz–1 MHz) was also analyzed, which may be interpreted by the Maxwell–Wagner-type polarization. The UV–vis–NIR reflectance curve was analyzed to calculate the bandgap of ferrites, which showed a decreasing trend with increasing sintering temperature.

Two series of Mn-Zn nanoferrites (namely Mn1-xZnxFe2 O4 and Mn1-xZnx Fe2-yRyO4) were synthesized using standard ceramic technique. X-ray diffraction and FT-IR were employed in the chacterization of the nanopowder. The X-ray density for each sample increased after laser irradiation which was correlated with the decrease in the unit cell volume. The study involved the thermal and frequency variation of the dielectric constant and AC conductivity of the investigated samples before and after laser irradiation. The later altered the conductivity by decreasing its value for the rare earth doped samples except for the Sm3+ doped one. The results suggested the exploitation of Mn-Zn doped rare earth nanoferrites in many technological applications demanding high resistivity. [ABSTRACT FROM AUTHOR]

Holmium (Ho3+) substituted Yttrium Iron Garnets (YIGs) Y3-xHoxFe5O12 (x = 0.1, 0.3, 0.6, 0.9, 1.5) prepared by conventional ceramic technique are reported in this article. X-rays diffraction data showed well-defined peaks of Holmium-YIG. The crystallite size calculated by Scherer formula increased from 66 nm to 123 nm with the addition of Holmium (Ho) contents. SEM micrographs show that the small crystallites agglomerated to make a big grain and the grain size lies in the range of (1.25 - 6.00 µm) for all the samples. The saturation magnetization (Ms) and remanance (Mr) enhanced withadditives. A noticeable decrease in the coercivity with the increase of Ho composition is also observed. It is worth noting that the substitution of Ho3+ makes the YIG better soft magnetic material which may be used in electronic devices like guided wave oscillators. These magnetic garnets have high utilization in magnetic bubble domain type memories. Furthermore, these substituted magnetic garnets have wide applications in optical devices like magneto-optical disks and displaying optical instruments. High technological utilization of this Ho-YIG series in telecommunication and defense industry can also be explored and apprehended. [ABSTRACT FROM AUTHOR]

Abstract: Modifying the proportion of the base composition by substituting with suitable dopents and improving the preparation conditions is expected to change the performance of composites. In the present study, 0.5(Ni0.5Zn0.5Fe2O4)/0.5(BaTiO3) composite was prepared by, the conventional ceramic technique and the citrate method. Ceramic particles, when prepared via different routes, would demonstrate different properties, even with the same starting compositions. With the help of X-ray diffraction, scanning electron microscope (SEM), magnetic properties, and electric properties of the composites have been compared. A critical comparison of those methods is needed to make the best choice for given boundary conditions of targeted eventual material properties, raw materials, investment, processing and waste disposal costs. [Copyright &y& Elsevier]

Positive temperature coefficient resistance (PTCR) materials of Gd and Cr co-doped BaTiO3 ceramics were prepared by well known solid state reaction method. Temperature dependent electrical studies were performed in the temperature range from 300 K to 673 K. Curie temperature of the samples are around 345 K to 385 K. Resistivity was maximum at low temperature and decreases as the temperature increases confirming the semiconducting behavior and PTCR property of the synthesized nano-sized compounds. Thermoelectric properties demonstrated n-type semiconductor characteristics from room temperature to 673 K. [ABSTRACT FROM PUBLISHER]

In the current study, we explored the influence of structural, morphological, and magnetic properties of diamagnetic aluminum (Al3+) ions substituted nickel-zinc-cobalt (Ni-Zn-Co) spinel ferrites synthesized by the conventional ceramic technique. Single-phase cubic spinel structures with the Fd3m space group of Ni 0.4 Zn 0.35 Co 0.25 Fe (2‐x) Al x O 4 (0 ≤ x ≤ 0.12) ferrites were confirmed by the Rietveld refinement of X-ray diffraction (XRD) data. The lattice constants showed a decreasing trend with Al contents. Field Emission Scanning Electron Microscopy (FE-SEM) was used to observe the surface morphology. The average grain size estimated from the FE-SEM microstructures was found to be 0.55–0.38 µm for the studied samples. Fourier transform infrared (FT-IR) spectra identified two prominent absorption bands from 579.82–584.39 cm‐1 and 399.82–405.03 cm‐1 corresponding to the tetrahedral and octahedral voids, respectively. The modes' peak positions were both red-shifted and blue-shifted, as demonstrated in the Raman spectra. Cations distributions were identified by the Mossbauer spectra and from the Rietveld refinement. The concentrations of iron (Fe3+) ions in the sub-lattices were determined using Mossbauer spectra analysis. The maximum saturation magnetization (M s) was found to be 93.06 emu/g for the sample with x = 0.12. Overall, the obtained results indicate the applicability of the ferrite for high-frequency electronic devices. • Ni 0.4 Zn 0.35 Co 0.25 Fe (2‐x) Al x O 4 composites were synthesized by conventional ceramic technique. • The single phase cubic structure was confirmed by the XRD spectra. • Cations distributions were identified by the Mossbauer spectra and from the Rietveld refinement. • The maximum saturation magnetization (M s) was found to be 93.06 emu/g for the sample with x = 0.12. [ABSTRACT FROM AUTHOR]