Ab Initio Calculations of the Magnetic Properties of Bimetallic Alloys

摘要: Magnetic recording technology is ubiquitous in the modern world and constitutes a corner stone of current research development. Recent inventions such as heat-assisted magnetic exchange-coupled media has focused towards alloys exhibiting strong magnetocrystalline anisotropies. In this thesis, we investigate, from first principles using screened Korringa-Kohn-Rostoker method, effect range compositional microstructural defects features upon anisotropy energy (MAE) FePt CoPt alloys. We show that localised Pt alloying affects MAE bulk Co primarily through Pt-induced effects on sites. demonstrate stacking faults often reduce composite not necessarily additive, but synergistic. By varying unit cell geometry parameters FePt, formation complete Fe layers is, generally, dominant factor maintaining large MAE. investigate properties (spin moments, exchange) across an Fe/FePt/Fe multi-layer effective exchange exhibits reduction at Fe/FePt interfaces whole multilayer system very slightly reduced by presence interfaces. Across all systems, observe faults, incur relatively long-ranged spatial oscillations MAE, which may, turn, cause significant finite-size nano-scale.