In this present study, we have reported the synthesis of ZnMn2O4, transitional metal oxide by sol–gel method. The structural and morphological properties are confirmed using various characterization techniques namely XRD, FT-IR and SEM with EDX. Dielectric studies of ZnMn2O4 are measured at the frequency varying from 50&nbsp;Hz to 5&nbsp;MHz for the temperature range of 303–573&nbsp;K. The temperature dependent electrical parameters like impedance and modulus exhibit a strong correlation with the grains, grain boundaries and space charge effects in the synthesized material. Diffusion of oxygen vacancies in the dipoles and defects in the material due to oxygen vacancy complexes are investigated by the activation energy obtained from Arrhenius plot. It was found that the relaxation process was dominated by the hopping mechanism between the Mn3+ and Mn4+. Nyquist plot of impedance was attributed to the existence of space charge interface, grain boundary and grain conduction mechanism of the material. © 2016, Springer Science+Business Media New York.

Ruban Kumar A

Department of Physics

School of Advanced Sciences

Vellore Campus

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

Journal of Materials Science: Materials in Electronics

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

Nanosized particles of La0.9Dy0.1MnO3 were prepared by sol–gel technique using citric acid as a chelating agent. The compound was analysed by powder X-ray diffraction technique and found to be single-phased orthorhombic in structure with space group Pnma which was confirmed with standard JCPDS data. The structural and morphological characterisations of synthesised material were carried out using XRD, Fourier transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectrometer. The magnetic study at room temperature shows the paramagnetic behaviour of the material. The existence of space charge polarisation and relaxation is due to the presence of oxygen vacancy illustrated from the real and imaginary part of impedance, respectively. The activation energy of synthesised material is calculated using Arrhenius equation from the impedance spectroscopy which corresponds to the existence of oxygen vacancy. © 2017 Informa UK Limited, trading as Taylor &amp; Francis Group.

Materials Research Innovations

Structural and electrical properties of La0.9Dy0.1MnO3 prepared by sol–gel technique

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

In this work, nanostructure FeMnO3 perovskite material was synthesis by sol–gel auto combustion method using the glycine as a chelating agent for the first time in the literature. The synthesized materials were investigated structural, electrical, and magnetic properties by various characterization techniques. The X-ray diffraction reveals that the density and specific surface value are 2.54&nbsp;g/cm3 and 1.468&nbsp;m2/g, respectively. FE-SEM investigated surface morphology in the nanoscale region. The FeMnO3 material is existing antiferromagnetism at room temperature. Electrical property such as dielectric constant, tangent loss, and impedance spectrum, Nyquist plot with an equivalent circuit, AC conductivity, and electric modulus was analysed. The real part of permittivity, dielectric tangent loss with varying with temperature shows that the behaviour of Maxwell–Wagner relaxation in the FeMnO3 might be observed oxygen vacancy. The Nyquist plot gives more information-related electrical conduction process and individual contribution of grain and grain boundaries. The resistance (Ω) and capacitance (farads) values are varied with increasing temperature. An electric modulus value is varied under suppression electrode polarization and shows the effect of bulk and grain boundaries. © 2017, Springer-Verlag GmbH Germany.

Applied Physics A

Structural, magnetic, and electrical property of nanocrystalline perovskite structure of iron manganite (FeMnO3)

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.

Journal	Data powered by TypesetJournal of Materials Science: Materials in Electronics
Publisher	Data powered by TypesetSpringer Science and Business Media LLC
ISSN	0957-4522
Open Access	No