D.R. Mane

Permeability and magnetic properties of Al3+ substituted Ni0.7Zn0.3Fe2O4 nanoparticles

In this work, the structural and magnetic properties of Al3+ substituted Ni-Zn ferrite powders were investigated. Ni0.7Zn0.3AlxFe2−xO4 (where x = 0.0–0.5) powders were obtained by sol-gel auto combustion method. X-ray diffractometer, vibrating sample magnetometer, scanning electron microscopy, infrared spectroscopy, and permeability were used to study the effects of Al3+ ions on the structural and magnetic properties. X-ray patterns reveal that all the samples have single-phase cubic spinel structure. Infrared spectroscopy was used to locate the absorption bands and to study the influence of Al3+ substitution on the spinel structure of the presently investigated system. The lattice constant and x-ray density were calculated from the XRD data. The density of the samples was measured and consequently the porosity was calculated too. Magnetic properties were carried out by means of magnetization measurement to study the magnetic interaction between the ions. This paper is also focused its discussion on the d...

Structural properties and magnetic interactions in Al3+ and Cr3+ co-substituted CoFe2O4 ferrite

A series of CoAlxCrxFe2−2xO4 systems (x = 0.1 to 0.5 in steps of x = 0.1) spinel ferrites have been synthesized successfully using wet chemical co-precipitation technique. The samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR) and magnetization measurements. The powder XRD patterns confirm the single phase spinel structure for the materials synthesized. X -ray diffraction measurements were performed to yield the lattice constant as function of the amount x corresponding to Al-Cr substitution. Lattice parameters, X-ray density, bulk density and particle size decrease whereas porosity increases with the increase in Al-Cr content, ‘x’. Infrared studies show two absorption bands at about 400 cm−1 and 600 cm−1 for octahedral and tetrahedral sites, respectively. Saturation magnetization decreases with the increase in Al-Cr content x. AC magnetic susceptibility measurements were carried out as a function of temperature to measure the Curie temperature, which was found to decrease with Al-Cr content x. The decrease of Curie temperature has been explained by A-B interaction.

Rietveld Structure Refinement and Cation Distribution of Cr

Ferrite nanoparticles of Ni0.7Zn0.3Cr𝑥Fe2−𝑥O4 were prepared by a sol-gel autocombustion method. The prepared samples were shown to have a cubic spinel structure by applying the full pattern fitting of the Rietveld method. The unit cell dimension, discrepancy factor, and interatomic distance have been determined. As the Cr3

Intrinsic magnetic, structural and resistivity properties of ferromagnetic Mn{sub 0.5}Zn{sub 0.5}Al{sub x}Fe{sub 2−x}O{sub 4} nanoparticles

In this work the nano-structural, magnetic and resistivity properties of Al3+ substituted Mn–Zn ferrites powders were investigated. Mn0.5Zn0.5AlxFe2−xO4 powders, where x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 were obtained by the sol–gel auto-combustion method. X-ray diffraction data indicate that, after substitution, all the samples consisted of the main spinel phase in combination with a small amount of a foreign Al2O3 phase. The addition of Al3+ resulted in a reduction of particle size and density of the prepared samples. Cation distribution in the present study was estimated by using X-ray diffraction data. The tetrahedral site radii initially increased with Al3+ content while the octahedral site radii decreased with the Al3+ substitution. FTIR spectra show two strong absorption bands at 529–548 cm−1 and 445–452 cm−1 which are the typical bands for the cubic spinel crystal structure. The magnetic properties were measured by employing a vibrating sample magnetometer. It was observed that the saturation magnetization, coercivity and anisotropy field decreased with the increase of Al3+ substitution. Introduction of Al3+ ions into the Mn–Zn ferrite increased the values of the resistivity, especially in the lower temperature range.

PHYSICO-CHEMICAL, STRUCTURAL AND ELECTRICAL STUDIES OF Cu–Zn FERRITES SYNTHESIZED BY NOVEL CHEMICAL ROUTE

The physico-chemical, structural and electrical properties of zinc substituted copper ferrites having the general formula Cu1-xZnxFe2O4(x=0.0 to x=0.8) have been studied as a function of zinc ion concentration. The sample was prepared by co-precipitation method from corresponding metal sulphates. X-ray diffraction patterns were used to confirm the structure of synthesized samples. The calculated and theoretical values of average lattice constant, tetrahedral bond, tetrahedral edge and unshared octahedral edge were found to increase, while the shared octahedral edge and octahedral bond decrease as the Zn ion concentration increases. The dielectric constant (e′) and dielectric loss tangent (tan δ) were measured at a constant frequency 1 kHz as a function of temperature. The dielectric constant and loss tangent were found to increase with rise in temperature. The conduction mechanism in these ferrites is discussed on the basis of electron exchange between Fe2+ and Fe3+ ions. The temperature dependent dc resistivity was carried out in the temperature range 300 to 800 K. The plots of log ρ versus 103/T are linear showing two regions, corresponding to ferrimagnetic and paramagnetic regions.