الفهرس 
Introduction and Literature SurveyOnly 14 pages are availabe for public view
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Abstract
Positron annihilation lifetime spectroscopy (PALS) has been adopted to index and notify the various defects in Zn(1-x)Ni(x)O.
A fast-fast coincidence system with a time resolution (FWHM) of 230 ps was used. A positron source of radioactive 22NaCl was sandwiched between two identical samples. The lifetime spectra plotted by almost 1.2×106 counts.
The structural properties of these samples have been studied by X-ray diffraction (XRD) and Transmission electron microscope (TEM).
Furthermore, magnetic properties have been studied like that ”(M-H) curves”.
The optical properties have been investigated by (UV-Vis) spectrum and Fourier Transform infrared (FTIR).
Hereafter the thesis can be summarized in:
List of figures
List of tables
Chapter 1: Introduction and Literature Survey
Shows up an introduction about dilute magnetic semiconductors (DMS) and positron annihilation spectroscopy. Also, contains the previous work of the prepared samples.
Chapter 2: Theoretical Background
This chapter gives a general presentation of positron annihilation behavior in solids and semiconductor.
Chapter Three: Experimental Techniques and Sample Preparation
This chapter consists of three parts:
• The first part explains the crystal structure and sample preparation of the Zn(1-x)Ni(x)O system.
• The second part consists of description for the X-Ray Diffraction (XRD) and (TEM), optical techniques and magnetic measurements.
• The third part describes the components of Positron Annihilation Lifetime Technique.
Chapter Four: Results and Discussion
This chapter contains a discussion of the results concerning the structural, optical, magnetic properties and the positron annihilation lifetime spectroscopy calculations for
(Zn(1-x)Ni(x)O, 0% ≤ x ≤ 10%) by using six techniques:
1- Transmission Electron Microscope confirmed that the composite record in the extent of nano-scale.
2- The emergence of nickel oxide peaks in the X-ray patterns was after the concentration of 5%, also, the variation of crystal size, lattice parameters and internal strain with nickel concentration has been calculated.
3- Calculation of energy gap from (UV-Vis) spectroscopy.
4- Study of vibrational modes from Fourier Transform infrared (FTIR).
5- Determination of magnetic properties using (M-H) curves, and calculate the variation of saturation magnetization with nickel oxide concentration.
6- Calculation of positron annihilation lifetime in defects within the sample, then study the interrelationship between lifetime, lattice parameters and internal strain. Also, the study of the rate of change between the trapping rate and energy gap has been investigated. Finally the correlation between positron annihilation lifetime within open free volumes and saturation magnetization with a different concentration of nickel oxide within the samples evidenced the origin of ferromagnetism inside samples .