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Spinel ferrites are vital in developing next-generation technologies with potential applications covering the medical, electronic, and material industries. Nickel-cadmium spinel ferrites are soft magnetic materials having lots of applications ranging from electronics and magnetic to sensors industries. Herein, we developed cadmium-substituted spinel ferrites (Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4) and their nanocomposite with polymer polyvinyl alcohol (PVA). The results evidently indicate that the successfully developed Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4, which also confirmed the loading of PVA onto the Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4 materials. XRD results confirmed orthorhombic single-phase structure. The optimal particle size was 27.22 nm, and the minimum was 21.25 nm, respectively, as shown by Ba 0·5 Ni 0·1 Cd 0·4 Fe 2 O 4 (x = 0.4) and PVA composite of Ba 0·5 Ni 0·2 Cd 0·3 Fe 2 O 4 (x = 0.3). It was also observed that the composites showed lower particle size than nano-ferrites. Spectral analysis (Fourier Transform Infrared Spectroscopy) confirmed the formation of spinel ferrites by detecting the M − O bonds in the 400-800 cm−1 region. υ 1 and υ 2 were appeared in the range 560–609 cm−1 and 439-466 cm−1, corresponding to M-O. The average grain size of spinel ferrites was 0.55, 0.50, 1.03, and 1.31 μ m for Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4 (x = 0.1, 0.2, 0.3, and 0.4) spinel ferrites. Dielectric parameters revealed that these materials are suitable for high-frequency devices due to their low dielectric loss, high quality factor, short relaxation time, and diverse responses. [ABSTRACT FROM AUTHOR]

The x-type hexaferrites have been getting considerable attention owing to their promising application in electronic fields. Though, the growth of nanosized crystal X-type hexagonal ferrites is still a big challenge. Herein, the synthesis of nanosized X-type hexagonal ferrites Ca 2 Co 2−x Zn x Fe 28 O 46 (X = 0.0, 0.4, 0.8, 1.2, 1.6, and 2.0) with high quality is reported using the auto-combustion sol-gel method. The objective of the study was to improve the structural and dielectric properties of X-type hexagonal ferrite which was achieved through variation of concentration of cobalt and zinc. Structural, morphological, and dielectric properties were investigated. X-ray diffraction (XRD) patterns confirmed the single-phase x-type hexagonal structure. The crystal size of all samples was in the range of 22.7–23.8 nm. Other parameters such as d -spacing, lattice parameters, unit cell volume, dislocation density, atomic packing fraction, degree of crystal lattice distortion, number of the unit cells, and volume of particles were also calculated. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of metal oxide bonds with two absorption bands at 574 cm−1 and 424 cm−1. The morphology of the prepared Ca 2 Co 2−x Zn x Fe 28 O 46 with the variation of Co and Zn was examined by scanning electron microscopy. Increasing crystallinity and agglomeration were observed with the upsurge in Zn and Co. The dielectric properties of Ca 2 Co 2−x Zn x Fe 28 O 46 with the variation of Zn and Co revealed that these materials might be considered good candidates for modern devices. [Display omitted] • Nanosized X-type hexagonal ferrites was synthesized by auto-combustion sol-gel. • Crystal size of all samples was in the range of 22.7–23.8 nm. • Dielectric properties revealed that materials are good candidate for devices. [ABSTRACT FROM AUTHOR]

• Reinforcement of polyvinyl alcohol (PVA) nanocomposites blend using Mg 0.5 Zn 0.5 Fe 2 O 4 nanoparticles. • The interaction of PVA and nanoparticles in nanocomposites samples was confirmed by FTIR, which showed shifting bands in FTIR spectra. • Loss factor and dielectric constant show a decreasing trend, with variable amounts of nanoparticles and constant polymer concentration. Significant progress has been done in the synthesis of polymer nanocomposites owing to their great application in various fields like in devices, limiting diodes, photodetectors, solar cells, and spin-coating. The present study deals with the incorporation of polyvinyl alcohol (PVA) nanocomposites blend using Mg 0.5 Zn 0.5 Fe 2 O 4 nanoparticles. The Micro-emulsion method has been utilized to synthesis Mg 0.5 Zn 0.5 Fe 2 O 4 nanoparticles and after that implanted into PVA network via ultrasound-assisted liquid-phase approach. This method can be used to solve problems with nanoparticles dispersion and stabilization in the PVA matrix. Under ultrasonication, the aggregation of nanoparticles was found to be reduced. Transmission electron microscopy (TEM) revealed that PVA chains have encircled the Mg 0.5 Zn 0.5 Fe 2 O 4 nanoparticles, which is further verified by Fourier-transform infrared spectroscopy (FTIR) peak shifting values. The X-ray diffraction (XRD) patterns demonstrated that the composite crystalline structure is single-phase cubic. The crystallite size for the largest peak (1 1 1) increases gradually from 31.49 to 43.79 nm by increasing the concentration (0.1–0.5 g) of nanoparticles with PVA. The interaction of PVA and nanoparticles in nanocomposites samples was confirmed by FTIR, which showed shifting bands in FTIR spectra. Loss factor and dielectric constant show a decreasing trend, with variable amounts of nanoparticles and constant polymer concentration. The dielectric properties of with variation of nanoparticles revealed that these materials might be considered a good candidate for modern devices like memristors, and Random access memories (RAM). [ABSTRACT FROM AUTHOR]

Erbium-doped nanocrystalline, Cu-ferrites, chemically known as CuFe 2–x Er x O 4 (x = 0.04, 0.08, 0.12, 0.16, 0.20) were synthesized. The effects of Er3+-doped on magnetic, structural and dielectric behaviour of CuFe 2 O 4 were studied by XRD, Scanning Electron Microscope (SEM), TGA, FTIR, VSM, and dielectric analysis. The CuFe 2–x Er x O 4 ferrites crystallize in spinel cubic structures with ex ≤ 0.12. SEM data demonstrated that their spherical morphology and crystalline size was <50 nm. The XRD spectra of all the prepared samples exhibited peaks of single-phase spinel ferrites. The lattice parameter (A) was amplified with the ascent of Er3+ concentration in the latticework. The FTIR patterns of the synthesized ferrites described the asymmetric stretching mode of spinel transition AB 2 O 4. SEM photography confirms that the particle size had developed up to 500 nm after doping of Er3+. The maximum saturation magnetization (Ms ~ 38.01 emug−1) was observed for CuFe 2 O 4. It was found that the decreasing in temperature leads to the great enhancement in the magnetic properties of the examined samples. As the magnetic recording performance of the magnetic samples is enhanced for well-crystallized samples with nano-structural, the effect of Er3+ substitution appears to be particularly valuable in this respect. [ABSTRACT FROM AUTHOR]