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Investigation of the structural, electronic and magnetic properties of full-Heusler Co2VIn as well as half-Heusler CoVIn Cobalt based Heusler compounds using density functional theory (DFT) leads to the general conclusion that Co2VIn and CoVIn are half-metallic materials with a gap at the Fermi level in the minority states and majority states respectively. A Hubbard-like Coulomb correlation term U has been included in the DFT (DFT+U) for the computation of the electronic and magnetic properties of the compounds. The structural properties have been calculated for the paramagnetic and ferromagnetic phases, and both Co2VIn and CoVIn are found to be stable in the ferromagnetic phase. The calculated magnetic moments are 2 μB and 0.9 μB per formula unit for Co2VIn and CoVIn respectively.

The investigation of the magnetocrystalline anisotropy of 5f transition-metal atoms is discussed. The cubic and uniaxial exchange-controlled anisotropies have similar magnitude and exhibit similar temperature dependences.

Research into relaxation processes in disordered nanostructures and spin glasses is presented. It was possible to develop a one-dimensional model which indicates that exchange inhomogenities produce a cooperative glass transition at a temperature much above the (trivial) phase-transition temperature Tc=0.

A generalized n-vector model has been used to investigate anisotropic two-sublattice magnets, with emphasis on the effects of two-sublattice anisotropy on the Curie temperature and the finite-temperature behaviour of net anisotropy. This is treated in a mean-field approximation. The anisotropy contribution to the Curie temperature was determined by the transition-metal sublattice.

Electron localization is a well-known problem, where metallic wave functions are delocalized. Electrostatic correlations and disorder can give rise to Mott and Anderson localization. The Anderson localization is considered in a random potential. An interpretation of micromagnetics in terms of the localization problem is presented, with particular focus on nucleation modes and long-time magnetic relaxations.

A combination of the x-ray diffraction and transmission electron microscopy techniques is employed to explain the fabrication and the properties of the Ti:TiO core-shell nanoparticles. An increase in the thickness of the TiO shell is shown to lead to an increase in the magnetic moment of the system.

Several studies are conducted to explain the structural, magnetic, as well as the magneto-transport properties of the various different Pt-alloyed MnBi thin films. An increase in the concentration of Pt in the films is shown to lead to a decrease in their saturation magnetization.

The magnetic-force microscopy technique is employed to explain the various magnetic antiphase domains observed in the Co/Ru/Co trilayers. The thickness of the trilayers is shown to exhibit an inverse relationship with the magnetic field.

Nanoclusters of rocksalt TiO, anatase Ti[O.sub.2] and rutile Ti[O.sub.2] are produced by cluster deposition and investigated with transmission-electron microscopy. The analysis of the measurements have shown that the magnetism is located near the surface the clusters and characterized by a nominal value.

Fabricated and characterization of nonepitaxial FePt:X films (X=Cu,Au,CuAu) with tunable magnetic properties are described. The studies have shown that Cu enters the [L1.sub.0] lattice whereas Au segregates at the grain boundaries and has reduced the intergranular exchange coupling.

Cobalt-doped boron carbides produced by simultaneous plasma-enhanced chemical vapor deposition of carborane and cobaltcene are examined. It is shown that the cobalt has strongly hybridized with the molecular orbitals of the icosahedral cage and the states in the region of the band gap have a strong cobalt weight.

The origin of the striking magnetic anisotropy of cobaltous oxide (CoO) is examined by using model calculations. A simple configuration-interaction approach is used to analyze the effect of 3[d.sup.8]-3[d.sup.6] bonds and their interplay with 3[d.sup.7]-3[d.sup.7] configurations.

A mean-field approach is used for calculating the magnetic entropy as a function of temperature, magnetic field, particle size, anisotropy and interaction strength. The studies have shown that the important feature of magnetic nanoparticles is that the entropy has displayed a strong dependence on the magnetic anisotropy.

Analytical and numerical calculations are used for examining the magnetization reversal in very small FePt particles. The nonrectangular hysteresis loops have reflected factors such as grain misalignment, particle-size distribution and different degrees of [L1.sub.0] order in different particles.

Model calculations are used for examining the temperature dependence of the spin polarization of half-metallic ferromagnets. The studies have shown that the gap reduction is a one-electron rather than a correlation effect and adds to the spin mixing.

Magneto-optical measurements are used to examine Pt-Co and Co layers exchange-coupled by a Pt layer. A ferromagnetic or acoustic and an antiferromagnetic or optic mode are identified from the Fourier-transformed excitation spectra and the line positions are used to estimate the interlayer exchange constants.

A complex hierarchy is used to determine the thermal stability of the information stored in magnetic recording media. Thermally activated reversal in very thin elongated nanoparticles has limited the thermal stability of magnetic recording media but has also degenerated into coherent rotation as the temperature is reduced, thus reconciling micromagnetism and thermodynamics.

The impact of magnetic impurities on the behavior of metallic clusters is investigated. A unique feature of the Hubbard-type interaction model is that the Kondo effect is reproduced by an unrestricted Hartree-Fock approximation.