الفهرس 
Orbital Angular Momentum
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Abstract
Basma El-Assy, Physics Dept., Faculty of Girls, Ain Shams
University.
The aim of this thesis is to perform a first-principles study on
the electronic structure and magnetic properties of some rare-earthtransition metal compounds RT5 (R = Y, Gd and Sm, T = Co) and the
compound with Boron RT4B (R=Sm, T=Co).
Our calculations are carried out self-consistently and based on
Density-Functional Theory (DFT) as implemented in the Wien2K
electronic code.
Energy dependence on the lattice parameter ratio c/a, total
density of states (DOS) in each compound and each crystal site and
the DOS in each effective state, and band structure in two different
directions in the Brillouin zone are calculated and discussed by using
the Wien2k code. We also report the total and local magnetic
moments in these compounds. These properties are attained in the
case of spin-polarized and spin-polarized with spin-orbit interactions.
These calculations showed that YCo5, SmCo5 and SmCo4B are
ferromagnets while GdCo5 is a ferrimagnet.
In addition, by using the methods of classical statistical
mechanics, we calculated the magnetization curves, the anisotropy
field and the probability landscape at room temperature. Also, we
discussed the dependence of the magnetization vector on the
direction of the magnetic field, along and perpendicular to the easyaxis. These calculations are carried out by Mathematica package and
showed that the c-axis is the easy axis of magnetization for these
compounds and also these compounds have high anisotropy at room temperature. Our calculations are in a good agreement with other
works.
This thesis is composed of three chapters, an abstract and a
conclusion section. In the first chapter, a brief history of the
compounds is discussed together and a review of magnetism and of
magnetic materials, magnetic interactions in rare earth transition
metal and energy bands in solids are given in some details. This is
followed by a survey of the theoretical investigation of the quantummechanical properties of systems with detailed explanation of
Density Functional Theory (DFT) in chapter 2. The results are
presented and discussed in chapter 3. Finally a conclusion on the
work is made.