Theoretical description of magnetic Compton scattering and magnetic properties of Cr-chalcogenide compounds

The subject of this work was to use the SPR-KKR formalism to
investigate the ground state properties of materials from
Cr-chalcogenide class and to describe the spectroscopic properties
(Compton scattering and possitron annihilation) of different
metallic systems. The fundamentals of the theoretical approach
applied is presented in Chapter 2. In particular, the basics of the
density functional theory used to reduce the many body
electron-electron interaction to single electrons moving
independently in an effective potential, together with the SPR-KKR
formalism used to solve the electronic structure problem are
discussed in detail. This theoretical formalism is applied to get
the description of the magnetic Compton profile, as it is shown in
Chapter 3, together with the results for pure metals, alloys and
ordered compounds. The formalism which describe the positron
annihilation os presented in Chapter 4. The 2D projection of the
electron-positron momentum density for V it was compared with the
experimental spectra and with the LMTO calculated spectra. A
complementary approach to investigate the magnetic behaviour of
solids using a microscopic model of the magnetic interaction was
combined with the SPR-KKR band structure calculations in order to
determine the magnetic ground state of CrSe and CrTe systems. The
influence of the exchange-correlation treatment on the equilibrium
lattice parameters for CrSexTe1-x alloy was investigated. The
magnetic moments and density of states for Cr5Te8 system
substituted with Se and Ti have been investigated, as can be seen
in Chapter 5.