الفهرس 
Literature surveyOnly 14 pages are availabe for public view
 |  | from | 267 |  |  |
| | | from | 267 | | |
Abstract
The mixed ferrites Li0.5-0.5x Nix Fe2.5-0.5x O4 (where x=0.0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0) were prepared from high purity oxides using the standard ceramic technique. The oxides were pressed under constant pressure of (3x108 Pa) to form pellets and toroides. The samples were finally sintered at 1200oC for 10hr.
Many techniques have been used to investigate the prepared samples as: X-ray diffraction and SEM to study the structure, Magnetization, B-H loops and initial permeability to study the magnetic properties.
X-ray diffraction analysis indicates that the investigated system were formed in a single phase cubic spinel structure. Also, the lattice parameter was calculated and found to have a constant value (0.83 nm ± 0.01) for all samples. Also, the lattice parameter was calculated theoretically by supposing a cation distribution for the studied samples and verifying a good fitting with the experimental calculations.
The analysis of IR spectra indicates the presence of splitting in the absorption band due to the presence of small amounts of Fe2+ ions in the ferrite system. The force constants for tetrahedral and octahedral sites have been determined.
The grain diameter was estimated from the SEM micrographs for all samples. The SEM micrographs indicate the distribution of grains with non-uniform size. The average grain diameter (D) of the samples was calculated from the SEM micrographs. The values of the grain diameter lie in the range between (6 and 14 μm).
Young’s modulus (E), rigidity modulus (G), bulk modulus (B), Debye temperature (θD), transverse (Vt) and longitudinal (Vl) wave velocities have been determined. The variation of elastic moduli with