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A series of Ti 0.9 Fe 0.1-x Ni x O 2 (x = 0.0, 0.02, 0.04, 0.06, 0.08, 0.1) has been synthesized through the solid state reaction method at annealing temperature of 1100 °C for two hours. The synthesized samples have been analyzed by X-Ray diffractometer (XRD), Raman spectroscopy, Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Vibrating sample magnetometer (VSM) and ultraviolet visible (UV–VIS) spectroscopy for structural investigations, defects measurements, surface morphology, magnetic and optical properties respectively. Structural analysis has revealed the dominant structure of rutile. An intensity loss and peak broadening of TiO 2 (rutile) vibration lines have been observed from Raman analysis, which is an indication of presence of oxygen vacancies. Magnetic analysis has revealed ferromagnetic behavior at room temperature. Optical characterization has shown the blue shift in band gap energy with increase of Ni concentration. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we present the effect of low substrate temperature on structural, morphological, magnetic and optical properties of Ba-hexaferrite thin films. Films were deposited on single crystal Silicon (100) substrate employing the Pulsed Laser Deposition (PLD) technique. The structural, morphological, magnetic and optical properties are found to be strongly dependent on substrate temperature. The low substrate temperatures (room temperature to 200°C) restrict the formation of larger grains. For the higher substrate temperature i.e., 400°C, the grain size of the deposited thin film are much larger. The film grown at low substrate temperature do not show any anisotropy. As the substrate temperature is increased, the easy axis of the films alinged itself in the direction parallel to the film plane whereas the hard axis remained in the perpendicular direction. The higher substrate temperature caused the uniaxial magnetic anisotropy, which is very important in magnetic recording devices. The saturation magnetization and optical band gap energy values of 62emu/cc and 1.75eV, respectively, were achieved for the film of thickness 500nm deposited at 400°C. Higher values of coercivity, squareness and films thickness are associated with the growth of larger grains at higher substrate temperature. [Copyright &y& Elsevier]

Abstract: Nickel Cadmium Aluminum Ferrites with the general formula Ni1−x Cd x Al0.6Fe1.4O4 where x=0, 0.25, 0.50 and 0.75 were prepared through standard double sintering reaction method. The crystallography, surface morphology and magnetic properties were studied by X-ray diffractometer (XRD), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM), respectively. The expected single phase spinel structure was confirmed by XRD analysis. Lattice parameter and X-ray density were increased monotonically by increasing Cd concentration due to the larger ionic radii of the cadmium ion. Surface topography of the samples consists of fine cubical shape microstructures. The average grain size increased with increase in cadmium concentration. The saturation magnetization was found to be increased with increase in cadmium content up to x=0.50 and then decreased with further increasing cadmium concentration for x=0.75. [Copyright &y& Elsevier]

In this research project a series of chromium substituted barium hexa-ferrites with formula BaCrxFe(12-x)O19 (x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) have been synthesized using powder metallurgy route, sintered at 1100 °C for 2 h. The structural, functional analysis, surface morphology, magnetic and ferroelectric properties have been investigated using X-ray diffractometer, Fourier infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer, and ferroelectric technique, respectively. The structural analysis reveals the formation of barium hexaferrite structure with minor secondary phase of Hematite α- Fe2O3 in first five samples. Surface morphology shows that all grains have definite grains shape and grain boundaries. VSM analysis revealed the antiferromagnetic loops due to existence of hematite phase in (x = 0 to x = 0.5) samples, whereas the sample (x = 0.6) shows the ferro-magnetic behavior. Ferroelectric measurement shows centrosymmetric and non-centrosymmetric orientation and maximum remnant polarization due to presence of more Fe2+ ions in (x = 0.1–0.5) so that not proper closing of first five samples enhanced the magnetoelectric (ME) coupling. [ABSTRACT FROM AUTHOR]