In this work, spinel FeCo2O4 is synthesized by sol-gel method using succinic acid as a chelating agent at 900 °C. The structural, spectroscopic and morphological characterization was carried out by using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy equipped with Energy Dispersive X-ray spectrometer (SEM-EDX). The M-H loop at room temperature confirms the ferromagnetic property of the sample. The frequency and temperature dependence of dielectric constant (ε) and dielectric loss (tan δ) shows the presence of Maxwell-Wagner relaxation in the sample due to the presence of oxygen vacancy. Nyquist plot for frequency and temperature domain signifies the presence of grain effect, grain boundary effect and electrode interface in the conduction process. Electric modulus under suppression of electrode polarization shows the grain and grain boundary effects. The electrode polarization is observed in the lower frequency range of the conductivity graph. © 2015 Elsevier Ltd. All rights reserved.

Kalainathan S

Department of Physics

School of Advanced Sciences

Vellore Campus

Ruban Kumar A

Lobo L.S

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

Superlattices and Microstructures

Hydroxyapatite doped with disparate ions is synthesized by Sol-gel technique. Hydroxyapatite is a widely bio-ceramic material for orthopedics and dental applications with weak mechanical strength. The hydroxyapatite doped with various ions which is often reported to enhance mechanical strength and to control bacterial infections. The aim of the work concentrates to improve the hardness of the material. Antibacterial activity enhances with the ions which combine with hydroxyapatite. These effects noticeably reveal that the hydroxyapatite can be well utilized with doping ions in order to develop their efficiency against the various bacterial strains. The effect of co-dopants investigated on their phase structure, bond formation, surface and optical properties are studied using X-ray diffraction technique, Fourier Transform Infra-red analysis, Atomic Force Microscopy and Ultraviolet–Visible spectroscopy. The crystalline size of all the synthesized materials varies from 39 to 49 nm. All the composites exhibit hexagonal crystal structure. The functional groups confirm the bonding formation of prepared samples. The surface roughness of hydroxyapatite were successfully analyzed and observed that the dopants increase the roughness. The dielectric property explains the space charge polarization is present at low frequency and negative temperature coefficient of resistance in the prepared samples. The addition of ions improves the mechanical properties of host materials, which well suitable for coating on implantation devices and for various medical applications. © 2019 Elsevier B.V.

Materials Chemistry and Physics

Study of structural, mechanical and dielectrical properties of ions doped apatite for antibacterial activity

Nanocrystalline FeMnO 3 was synthesized by sol-gel method using succinic acid as a chelating agent. The structural and morphological characterizations of the synthesized material were carried out by using XRD, FT-IR, and SEM with EDX. The hysteresis loop at room temperature shows the antiferromagnetic behavior of the material. The variation in the frequency and temperature dependent dielectric constant illustrated the Maxwell-Wagner relaxation in the sample. Nyquist plot illustrated the grains resistance at higher frequency whereas at lower frequency it is dominated by the grain boundary resistance. The electrical modulus also confirms the relaxation process. The activation energy calculation of impedance and modulus shows the existence of oxygen vacancy. XPS analysis confirmed the existence of oxygen vacancy and different oxidation states of Fe 3+ /Fe 2+ and Mn 3+ /Mn 4+ in the material. Conductivity studies of the material were analyzed and fitted by using Jonscher Power law. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

Ionics

Investigation on structural and electrical properties of FeMnO3 synthesized by sol-gel method

In this present study, we have discussed about the synthesis of spinel type ZnCo2O4 by sol-gel combustion method using glycine as a chelating agent. Structural and morphological verifications are carried out using XRD, SEM and the functional group confirmation by using FT-IR. The temperature dependent dielectric relaxation and conduction mechanism have been analyzed by using dielectric measurements, impedance spectroscopy and electric modulus studies in the frequency range of 50 Hz to 5 MHz between the temperatures 303 K and 593 K. Influence of oxygen vacancy on the behaviour of dielectric relaxation is due to the hopping mechanism between Co2+ and Co3+ sites due to the structural defect in the material. XPS measurement confirms the different oxidation state in Co-site and the existence of oxygen vacancy in the material. The conductivity of the material is studied with Jonscher Power law. © 2018 Elsevier B.V.

Journal of Non-Crystalline Solids

Structural and electrical properties of ZnCo2O4 spinel synthesized by sol-gel combustion method

Non magnetic material Ca2+ as a substitute in Cobalt ferrite (Co1 − xCaxFe2O4 x = 0.00, 0.05, 0.10 &amp; 0.15) is prepared by self auto combustion method. The synthesized samples were carried out for various characterizations such as X-ray diffraction, Field emission scanning electron microscope (FE-SEM), Dielectric measurement and Magnetic property. X-ray diffraction reveals the values of crystalline size, lattice parameter and x-ray density by using the standard formula. The saturation magnetization (Ms) decreases from 63.92 to 43.17 emu/g for x = 0.00 to 0.15 and the coercivity (Hc) increases gradually from 819.85 to 1312.32 Oe with the increase in Ca2+ concentration. The dielectric properties of synthesized nano materials were carried out at room temperature. The dielectric parameters such as tangent loss, Cole–Cole plot (Impedance, Modulus), and AC Conductivity were determined for various Ca2+ concentration. The frequency dependent dielectric dispersion behaviour of all the samples can be explained by the Maxwell–Wagner two-layer model along with Koop's phenomenological theory. As a result, Ca2+ substituted Cobalt ferrite is enhanced with their dielectric and magnetic property which is suitable for a memory device, recording media application and high frequency device. © 2018 The Physical Society of the Republic of China (Taiwan).

Chinese Journal of Physics

Synthesis, structural, dielectric and magnetic properties of spinel structure of Ca2+ substitute in Cobalt ferrites (Co1−Ca Fe2O4)

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.

International Journal of Nanoscience

Preparation of Magnesium-Based Cobalt-Ferrites (Co1−xMgxFe2O4) Nanoparticles by Sol–Gel Auto Combustion Method

Journal of Magnetism and Magnetic Materials

Structural and magnetic characterization and cation distribution of nanocrystalline Co x Fe 3−x O 4 ferrites

RSC Advances

Structural, dielectric and magnetic investigations on Al3+ substituted Zn-ferrospinels

Dalton Transactions

Conduction mechanism, impedance spectroscopic investigation and dielectric behavior of La0.5Ca0.5−xAgxMnO3 manganites with compositions below the concentration limit of silver solubility in perovskites (0 ≤ x ≤ 0.2)

ACS Applied Materials & Interfaces

High-Performance Lithium-Ion Battery and Symmetric Supercapacitors Based on FeCo2O4 Nanoflakes Electrodes

Journal of Applied Physics

Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

Investigation of electrical studies of spinel FeCo2O4 synthesized by sol–gel method

Journal	Data powered by TypesetSuperlattices and Microstructures
Publisher	Data powered by TypesetElsevier BV
ISSN	0749-6036
Open Access	No