Maheshkumar L. Mane

Enhanced magnetic properties of Dy3+ substituted Ni-Cu-Zn ferrite nanoparticles

Dy3+ substituted Ni-Cu-Zn (Ni0.4Cu0.4Zn0.2DyxFe2−xO4) ferrite nanoparticles were obtained at 600 °C by synthesizing sol-gel auto-combustion method, and they exhibit a particle size of 12–21 nm. X‐ray diffraction patterns confirm the presence of secondary phase of DyFeO3 and Fe2O3 for the Dy3+ substituted samples. Ni‐Cu‐Zn ferries doped with Dy3+ possess better grain structure and growth than that of pure Ni‐Cu‐Zn ferrite. The saturation magnetization increases remarkably up to 81 emu/g with increasing the Dy3+ ions. The increased saturation magnetization related to increased exchange interactions between Fe‐Fe ions and also with increased particle size. Blocking temperature was found to decrease with increasing Dy3+ substitution. An enhancement in initial permeability and Curie temperature was observed with Dy3+ substitution.

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...

Sol-gel auto-combustion synthesis of Li3xMnFe2−xO4 and their characterizations

Ferrite samples of Li+ substituted MnFe2O4 nano particles were synthesized by sol-gel auto-combustion method. The samples were obtained by annealing at relatively low temperature at 600 °C and characterized by x-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, and infrared (IR) spectroscopy. Lattice parameter, x-ray density, specific surface area, and porosity are found to increase, whereas bulk density and crystallite size showed the decreasing trend with the Li+ content. Splitting of major absorption bands related to Li+ substituted ferrites were observed in IR spectra. Substitution of Li+ ions for Fe3+ caused a decrease in the saturation magnetization from 75.69 to 58.57 emu/g and the coercivity increased from 157 to 308 Oe. DC resistivity decreases with increase in Li+ content. The temperature dependent results indicate that the values of dielectric constant (e′) and loss tangent (e″) increase with the increase in temperature.

Influence of Nd:YAG laser irradiation on AC impedance and dielectric properties of lithium ferrite

Polycrystalline samples of Li0.5Fe2.5O4 spinel ferrite have been synthesized by a standard ceramic technique. The samples were irradiated with an Nd:YAG laser to study the effect of laser irradiation on the structural, dielectric and AC impedance properties. The X-ray diffraction results show the formation of a disordered cubic structure after irradiation. The dielectric constant (ϵ′), dielectric loss (ϵ″) and the loss tangent (tan δ ) were measured at room temperature as a function of frequency (f=20 Hz–1 MHz) for the irradiated and unirradiated samples of Li0.5Fe2.5O4 spinel ferrite. The dielectric constant of the irradiated samples is decreased in magnitude compared to the unirradiated samples. It was found that laser irradiation increases the polarization and the resistivity of the samples as a result of electronic rearrangement and lattice defects. The AC conductivity of the samples was derived from the dielectric constant and loss tangent data. The change in AC conductivity is attributed to the creation of lattice vacancies after laser irradiation. The AC impedance analysis was used to separate the grain and grain boundary of the Li0.5Fe2.5O4 spinel ferrite.

Effect of Gamma Irradiation on the Physical Properties of Nanocrystalline Li0.5Fe2.5O4

The ferrite nanoparticles of Li0.5Fe2.5O4 spinel ferrite was synthesized by sol‐gel auto‐combustion technique using the nitrates of the respective cations at low temperature with a final pH 8. A part of as prepared powder was sintered at 700° C for 6 h and treated as the precursor for the gamma irradiation study. The damage investigations were evaluated on the basis of X‐ray diffraction and SEM techniques. The X‐ray diffraction data was used to investigate the phase purity and structural properties of the synthesized lithium ferrite. The lattice constant of studied samples were increased whereas crystallite size and grain size decreased after gamma irradiation.

Effect of Al3+‐Cr3+ Substitution on Structural, Cation Distribution and Magnetic Properties of MgFe2O4 Prepared by Chemical Co‐precipitation Method

The low temperature synthesis of Al‐Cr substituted MgFe2O4 ferrite system have been carried out using chemical co‐precipitation technique at 60 °C. The nanocrystallites of MgAlXCrXFe2−2XO4 ferrite system were characterized by X‐ray diffraction technique. The X‐ray diffractometer (XRD) showed the formation of single phase cubic spinel structure. Energy dispersive analysis of X‐rays (EDAX) showed the composition close to stichiometry of Al‐Cr substituted MgFe2O4. The most intense peak (311) of XRD patterns was used to calculate crystallite size of the samples and the crystallite size was found to be about 30 nm. The cation distribution which depends on the method of preparation and chemical composition has been determined by using XRD method. The saturation magnetization and magneton number obtained from hysteresis loop technique decreases as Al‐Cr content x increases. The decrease in magnetic behavior is attributed to decrease in A‐B interaction.

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.

Structural and Magnetic Characterization of BaFe12O19Nanoparticles

Barium hexaferrite nanoparticles have been synthesized successfully by using sol‐gel auto‐combustion technique. In this process dextrose and citric acid both used as a fuel separately. The ratio of cation to both the fuel was maintained at 1:3 whereas the pH of the sample was kept constant at 8. The particle size for dextrose and citric acid sample is 34 nm and 45 nm respectively. The room temperature hysteresis curve gives maximum magnetization (48.46 emu/g) and coercivity (1.350 kOe) values for dextrose used sample. The dextrose used sample gives better results than that of citric acid used sample.

Structural and Magnetic Characterization of BaFe[sub 12]O[sub 19] Nanoparticles

Barium hexaferrite nanoparticles have been synthesized successfully by using sol‐gel auto‐combustion technique. In this process dextrose and citric acid both used as a fuel separately. The ratio of cation to both the fuel was maintained at 1:3 whereas the pH of the sample was kept constant at 8. The particle size for dextrose and citric acid sample is 34 nm and 45 nm respectively. The room temperature hysteresis curve gives maximum magnetization (48.46 emu/g) and coercivity (1.350 kOe) values for dextrose used sample. The dextrose used sample gives better results than that of citric acid used sample.

Structural and Magnetic Characterization of BaFe12O19 Nanoparticles

Barium hexaferrite nanoparticles have been synthesized successfully by using sol‐gel auto‐combustion technique. In this process dextrose and citric acid both used as a fuel separately. The ratio of cation to both the fuel was maintained at 1:3 whereas the pH of the sample was kept constant at 8. The particle size for dextrose and citric acid sample is 34 nm and 45 nm respectively. The room temperature hysteresis curve gives maximum magnetization (48.46 emu/g) and coercivity (1.350 kOe) values for dextrose used sample. The dextrose used sample gives better results than that of citric acid used sample.