الفهرس 
Ferrite material
Experimental Aspects and TechniqueOnly 14 pages are availabe for public view
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Abstract
A set of Ni0.45Co0.45Sr0.1LaxFe2-xO4 samples, with varying values of x (from 0.00 to 0.10 by step 0.02), were synthesized using the flash auto-combustion method. The presence of the substituted La3+ ion in the system was verified via various characterization techniques, such as X-ray diffraction pattern (XRD), Fourier transformation infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Vibrating sample magnetometer (VSM), TGA, Dielectric Analysis, and Electrical Analysis. The X- ray diffraction pattern was confirmed the cubic spinel structure as a major phase, the crystallite size was determined from XRD increased by increasing lanthanum ion content up to x=0.04 then decrease again and ranged from 24 nm to 12 nm. The morphology of all samples was examined utilizing field emission scanning electron microscopy (FE-SEM). The grain size measured from SEM increased by increasing lanthanum content up to the sample of lanthanum content x= 0.04, then decreased above this value. The particle size measured from TEM has the same behavior of crystallite size measured from XRD. The saturation magnetization and magnetic parameters measured from VSM were enhanced by increasing the content of lanthanum up to x=0.04 then decrease again. At room temperature, the dielectric constant was studied for all samples ranging from 10-2 to 108 Hz. At high frequency, the rate of hopping increase and the ferrite become more conductive, causing a rapid decrease of ε′ and ε″. At lower frequencies, the inclusion of higher amounts of lanthanum leads to a reduction in the values of both ε′ and ε″. The rise in Lanthanum content above x=0.04 is associated with a DROP in electric conductivity, which can be attributed to the rule governing the increase in grain resistance, resulting in a increase in AC conductivity. The dielectric constant, dielectric loss, and resistivity as a function of temperature was measured as at different frequencies. At low temperature, all of them are independent of temperature. At high temperature, the dielectric constant increase due to thermal activation mobility of charge carriers. Thermal conductivity and thermal diffusivity increase with temperature. Due to its characteristics, this material may be ideal for thermoelectric and thermomagnetic sensors and switches.