Magnetische und Magneto-optische Eigenschaften von Nanostrukturen

Zsfassung in dt. SpracheIn the present work systematic studies of the magnetic and magneto-optical properties of nanostructures are presented.The first part is dedicated to the investigation of magnetic moments and the magneto-crystalline anisotropy of surface supported nanostructures.Starting from a case-study of a single adatom the dimension of the nanostructure is gradually increased to small clusters and then up to complete monolayers.The study is concentrated on the magnetic moments and the angular dependent band energy part of the magnetic anisotropy energy of single atoms of Fe and Co, which - in order to investigate the influence of different substrates - have been deposited on Pt(111), Ir(111) and Cu(100).For the composite FeCo nanoclusters deposited on a Cu(100) substrate three different geometries, i.e., 2x2, cross-like pentamer and 3x3, were considered in order to study the effect of the composition on the cluster properties.The calculations were performed within the spin-polarized, fully relativistic Screened Korringa-Kohn-Rostoker method (SKKR) using the embedding technique (ECM) for the adatoms and clusters. For the calculation of the magnetic anisotropy energy the force theorem was used.In the second part, it is emphasized and clarified on a first-priciples basis the role of surface layers played in ROTMOKE and also the layer-dependence of the magneto-crystalline anisotropy in the bcc Ni/Ni(100) system. The ROTMOKE geometry represents an intermediate setup between the longitudinal (LMOKE) and the transversal (TMOKE) configuration. For the bcc Ni multilayered system, the inter- and intra-layer contributions to the complex optical conductivity were determined by using the Luttinger formula and the SKKR method. The ab-initio Kerr angles were calculated via the 2x2 matrix technique for a linearly polarized light at oblique incidence within the 0yz plane. It is also shown that the calculated Fresnel coefficients can be applied using appropriate formulas, and thus Kerr angles for any arbitrary direction of a uniform in-plane magnetization can be determined.16