الفهرس 
Introduction and SurveyOnly 14 pages are availabe for public view
 |  | from | 227 |  |  |
| | | from | 227 | | |
Abstract
Preparation of nanoparticle ferrites has become a field of interesting research in the last two decades; where the magnetic nanoparticles can exhibit superparamagnetic phenomena and change their electrical and magnetic properties dramatically. Accordingly, new applications emerge and more and more researchers are involved in the field. The aim of the present work has been to prepare Cd0.5Cu0.5CrxFe2-xO4 nanoparticles (where x= 0.0, 0.05, 0.1, 0.2, 0.4, and 0.8). Part of prepared samples was annealed at 1000c for two hours. Then, study some structural, thermal, mechanical, magnetic, and electrical properties of the ferrites. A brief summary of the thesis chapters is as follows: Chapter 1: represents an introduction dealing with two main topics: 1. A brief overview of the importance of nano ferrites in modern applications and industries. 2. A survey of literature, with some helpful summaries of research work previously done by others related and/or useful in interpreting and justifying the current experimental work. Chapter 2: gives fundamental theoretical principles necessary to be reviewed before moving on to the main experimental work. For example, it includes a historical review of magnetism, types of magnetism, crystal structure of spinel ferrites, ferrites as important practical materials, theoretical basis of the used experimental techniques. Chapter 3: explains the preparation steps of the nanoparticle ferrites by using the co-precipitation method. Moreover, this chapter mentions the experimental techniques used to characterize and analyze our samples such as X-ray diffraction (XRD), FTIR spectroscopy, and transmission electron microscopy (TEM), Mossbauer spectroscopy, Thermo-gravimetric analysis (TGA). The vibrating sample magnetometer (VSM) used to study some of the magnetic properties is briefly overviewed also. The chapter includes also the techniques used to perform electrical measurements such as the DC conductivity by a Keithley electrometer as a function of temperature; and AC conductivity, dielectric constant, and loss tangent by the LCR impedance analyzer, where all these properties have been studied as functions of temperature and/or frequency. Schematic diagrams of the cell and circuits used in the experiments are also included. Chapter 4: includes a discussion of the obtained experimental results of: structural, thermal, mechanical, and magnetic of all nano ferrites samples. Chapter 5: includes a discussion of the obtained experimental results of: structural, mechanical, electrical, and magnetic of all bulk ferrites samples. Chapter 6: includes a discussion of the electrical and dielectric properties of all bulk ferrites samples.