One-dimensional lead hexaferrite (PbFe12O19) nanofibers are produced using electrospinning technology combined with sol–gel followed by muffle furnace heating. PVP/DMF is used as reductant to form precursor solution for lead hexaferrite nanofiber. Polycrystalline nanofibers with an average diameter of 145 nm have been prepared by electrospinning method. The structural features of the sintered nanofibers are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and EDX. The obtained PbFe12O19 nanofibers showed a hexagonal structure after sintering. The SEM image clearly shows the fibrous morphology of PbFe12O19. Vibrating sample magnetometer (VSM) revealed very low coercivity and fairly high saturation magnetization. The fiber exhibited a ferromagnetic behaviour at room temperature, which is attributed to the nanometre-size of PbFe12O19 nanofibers. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

Prathap R

Department of Computational Intelligence

School of Computer Science and Engineering

Vellore Campus

Madhuri W

Department of Physics

School of Advanced Sciences

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Applied Physics A

The effect of iron deficiency on the structural, electrical, ferroelectric and magnetic properties of nano PbFe12-xO19-δ (where x=0.0, 0.25, 0.50, 0.75, 1.0) hexaferrites prepared by sol-gel auto combustion and processed by microwaves are investigated. X-ray analysis confirms single phase magneto-plumbite phase formation. The surface morphology is studied from Field Emission Scanning Electron Microscope. Further, optical properties are investigated using Fourier Transform Infrared spectra and UV–visible spectra. AC electrical conductivity is estimated as a function of temperature and frequency in the range of room temperature (RT) to 500 °C and 100 Hz to 5MHz. AC electrical conduction analysis shows that conduction is mainly due to small polaron hopping mechanism. The variation of polarization with applied electric field exhibits hysteresis loop confirming the ferroelectric nature. The initial permeability studies with varying temperature reveals that the Curie transition temperature for the present series is around 400 °C. Variation of initial permeability with frequency ranging from 100 to 5 MHz shows a constant value (except for x=0.0) opening avenues for high frequency applications. © 2017 Elsevier B.V.

Journal of Magnetism and Magnetic Materials

Multiferroic properties of microwave sintered PbFe 12−x O 19−δ

Bulk and nano Ni1-xMgxFe2O4 (x = 0–1) samples were synthesized via microwave double sintering and microwave assisted hydrothermal techniques respectively. The diffraction pattern confirmed the formation of cubic spinel phases in case of both the ferrites. The larger bulk densities were achieved to the bulk than that of nano. In addition, a comparative study on X-band (8.4–12 GHz) electromagnetic interference shielding properties of current bulk and nanomaterials was elucidated. The results showed that the bulk Ni0.6Mg0.4Fe2O4 composition revealed the highest total shielding efficiency (SET) of ∼17 dB. In comparison, the shielding efficiency values of all bulk contents were higher than that of nano because of larger bulk densities. Moreover, the ac-electromagnetic parameters such as electrical conductivity (σac), the respective real (ε′ &amp; μ′) and imaginary parts (ε″ &amp; μ″) of complex permittivity and permeability were investigated as a function of gigahertz frequency. The bulk ferrites of x = 0.4 &amp; 0.6 showed the high ε″ of 10.26 &amp; 6.71 and μ″ of 3.65 &amp; 3.09 respectively at 12 GHz which can work as promising microwave absorber materials. Interestingly, nanoferrites exhibited negative μ″ values at few frequencies due to geometrical effects which improves the microwave absorption. © 2016 Elsevier B.V.

Materials Chemistry and Physics

Microwave processed bulk and nano NiMg ferrites: A comparative study on X-band electromagnetic interference shielding properties

Ferrites are magnetic semiconductors realizing an important role in electrical and electronic circuits where electrical and magnetic property coupling is required. Though ferrite materials are known for a long time, there is a large scope in the improvement of their properties (vice sintering and frequency dependence of electrical and magnetic properties) with the current technological trends. Forth coming technology is aimed at miniaturization and smart gadgets, electrical components like inductors and transformers cannot be included in integrated circuits. These components are incorporated into the circuit as surface mount devices whose fabrication involves low temperature co-firing of ceramics and microwave monolithic integrated circuits technologies. These technologies demand low temperature sinter-ability of ferrites. This article presents low temperature microwave sintered Ni–Mg ferrites of general chemical formula Ni1−xMgxFe2O4 (x=0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) for potential applications as transformer core materials. The series of ferrites are characterized using X-ray diffractometer, scanning electron microscopy, Fourier transform infrared and vibrating sample magnetometer for investigating structural, morphological and magnetic properties respectively. The initial permeability is studied with magnesium content, temperature and frequency in the temperature range of 308 K–873 K and 42 Hz–5 MHz. © 2016 Elsevier B.V.

Microwave processed NiMg ferrite: Studies on structural and magnetic properties

Separation and Purification Technology

Enhancement of magnetic, electrochemical and photocatalytic properties of lead hexaferrites with coating graphene and CNT: Sol-gel auto-combustion synthesis by valine

Journal	Data powered by TypesetApplied Physics A
Publisher	Data powered by TypesetSpringer Science and Business Media LLC
ISSN	0947-8396
Open Access	0