Gagan Kumar; Virender Pratap Singh; Arun Kumar; Jyoti Shah; Shalendra Kumar; B.S. Chauhan; R.K. Kotnala; M. Singh
Abstract
We investigated the effects of In 3+ and Co 2+ substitutions on the structural and magnetic properties of Mg-Mn ferrites. The cation distribution technique was taken into account to estimate the magnetic interactions. Cation distribution was also used to investigate the ionic radii of tetrahedral and ...
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We investigated the effects of In 3+ and Co 2+ substitutions on the structural and magnetic properties of Mg-Mn ferrites. The cation distribution technique was taken into account to estimate the magnetic interactions. Cation distribution was also used to investigate the ionic radii of tetrahedral and octahedral sites, oxygen positional parameter, site bond as well as edge lengths, bond lengths and bond angles. The ionic radius of tetrahedral site and octahedral site was observed to increase with the incorporation of In 3+ and Co 2+ ions respectively. Theoretical lattice parameter was observed to increase with the substitution of In 3+ and Co 2+ ions. In 3+ substitution resulted in weakening of super-exchange interactions while in Co 2+ substituted Mg-Mn ferrites, anisotropy was observed to play a decisive role in addition to bond lengths and bond angles.
Virender P. Singh; Gagan Kumar; Pooja Dhiman; R. K. Kotnala; Jyoti Shah; Khalid M. Batoo; M. Singh
Abstract
In the present work BaFe12O19 nano-hexaferrite had been synthesized by sol-gel method and then characterized for its structural, electric, dielectric and magnetic properties. X-ray diffraction studies confirmed the hexagonal structure of the prepared nanohexaferrite with no secondary phase and the particle ...
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In the present work BaFe12O19 nano-hexaferrite had been synthesized by sol-gel method and then characterized for its structural, electric, dielectric and magnetic properties. X-ray diffraction studies confirmed the hexagonal structure of the prepared nanohexaferrite with no secondary phase and the particle size was found to be of the order of 49 nm. Further, the morphology of the sample has been studied by using transmission electron microscopy (TEM). A high value of the DC resistivity (5.5 × 106 Ω cm), has been obtained at room temperature. The dielectric properties such as dielectric constant (ε′), dielectric loss tangent (tan δ) and ac electrical conductivity (σac) are investigated as a function of frequency. The dielectric constant and loss tangent are found to be decreasing with the increase in frequency while ac electrical conductivity is observed to be increasing with the increase in frequency. The dielectric properties have been explained on the basis of Maxwell-Wagner’s two-layer model and hopping of the charge. The magnetic properties such as initial permeability (µi) and relative loss factor (RLF) have been investigated as a function of frequency in the range 75 kHz to 30 MHz .Fairly constant value of initial permeability and low values of RLF of the order of 10-4 over a wide frequency range are the cardinal achievements of the present work. The room temperature M-H study shows that present nanohexaferrite has high value of coercivity (2151.3 Oe) and high saturation magnetization (32.5 emu/gm), which make present nanohexaferrite very suitable for magnetic applications. The M-T study shows that prepared nano-hexaferrite has high Tc (746 K).
Gagan Kumar; Ritu Rani; Vijayender Singh; Sucheta Sharma; Khalid M. Batoo; M. Singh
Abstract
Co 2+ substituted Mg-Mn nanoferrites having formulae Mg0.9Mn0.1CoxFe2-xO4, where x = 0.0, 0.1, 0.2 & 0.3, have been prepared for the first time by solution combustion technique. The magnetic properties of nanoferrites such as M-H, initial permeability (μi) and magnetic loss tangent (tan δ) ...
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Co 2+ substituted Mg-Mn nanoferrites having formulae Mg0.9Mn0.1CoxFe2-xO4, where x = 0.0, 0.1, 0.2 & 0.3, have been prepared for the first time by solution combustion technique. The magnetic properties of nanoferrites such as M-H, initial permeability (μi) and magnetic loss tangent (tan δ) have been investigated as a function of frequency in the range 700 Hz to 30 MHz. X-ray diffraction patterns confirmed the formation of single phase spinel structure of all the nanoferrites. The surface morphology of the samples is studied by using scanning electron microscopy (SEM), while elemental compositions of samples are studied by energy dispersive X-ray analysis (EDAX). Saturation magnetization (Ms) and magneto-crystalline anisotropy constant (K1) are found to be increasing with an increase in cobalt content while initial permeability and magnetic loss tangent are found to be decreasing with an increase in frequency as well as with the increasing concentration of Co 2+ ions. The very low values of magnetic loss tangent even at high frequencies are the prime achievements of the present work.
