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The influence of external field on thin ferromagnetic films with spin-reorientation transitions (SRTs) is explored in the presence of different orders of thickness-dependent uniaxial anisotropy. The two principal configurations are addressed and the first two anisotropy contributions are examined. A simple and natural representation of the field-induced SRTs has been found. It preserves the linearity of the thickness-driven trajectories even with field. The crosspoints of these trajectories with the phase borderlines correspond to crossover thicknesses of a linear type for positive second-order anisotropy contributions and of both linear and nonlinear types for negative second-order anisotropies. In the latter case, the nonlinear boundaries correlate with the coexistence of phases which brings about first-order-like reorientations and concommittant hysteresis effects. Practical schemes are proposed for the determination of the complete set of anisotropy parameters from measured field dependences of the crossover thicknesses. Index Terms - Anisotropy, ultrathin films

A method for the analysis of hysteresis in the H space of a uniaxial ferromagnet with higher-order anisotropy is proposed. Analytic expressions are the base for construction of generalized astroids to any order. In n>1, new features were observed and interpreted in relation to rotational hysteresis. The shape and symmetry of the critical boundaries depend critically on up to n-1 ratios.

Magneto-optical Kerr effect studies in ultrathin cobalt films reveal the temperature-dependent sharp maximum of the ac susceptibility to be related to ferromagnetic-paramagnetic phase transition at Curie temperature Tc. Magnetic properties of the films in paramagnetic regions above Curie temperature are also measured by this method.

The magnetic characteristics of ultrathin epitaxial fcc Co(001) thin films grown on Cu(113) terraced substrates were investigated using in situ magneto-optic Kerr effect measurements. The results showed that the films exhibited easy magnetization along the steps but there were unusual hard axis Kerr loops detected near room temperature. When the temperature was raised, these loops evolved toward soft magnetic behavior.

Fourier transform holography (FTH) is used for studying the nanostructured Co/Pt multilayer films with 40 nm spatial imaging resolution. The focused ion beam (FIB)-induced anisotropy modulation and the perpendicular domain structure is examined in the nanostructured samples, which has shown how to control the domain size and configuration by applying proper ion dose either homogeneously or concentrated in single spots.

The Poisson equation is used to explain the impact of the tilted edges on the various different magnetostatic properties of the uniformly magnetized thin rectangular elements. The results show that the presence of the tilted edges lead to an increase in the critical distance between the elements in the system.

An analytical and numerical study is carried out to study the influence of nonlinearities on static ellipsometry. A method is developed to reveal the magnetic properties with high accuracy in spite of the nonlinearities due to the optical setup and the applicability of this method is demonstrated.

Monte-Carlo simulations have been used to investigate the magnetization reorientation in second-order perpendicular anisotropy approximation. There was found to be an influence of the second-order perpendicular anisotropy on the spin reorientation transition when K(sub eff) vanishes.

The magnetic anisotropy of Co thin films deposited on Cu(001) and Cu(1113) substrates were investigated using Brillouin light scattering analysis. The results showed that films with thicknesses greater than 1.6 ML uncovered and 1.9 ML covered exhibited a ferromagnetic order. The surface normal was a magnetic hard axis and no volume out-of-plane contribution was detected. It was proposed that the symmetry breaking interaction for stabilizing ferromagnetic order at room temperature was given by the magnetic in-plane anisotropy.

Presents images of the magnetic domains of iron(100) surfaces using energy-resolved photoemission microscopy. Forms of magnetic dichroism in direct photoemission and secondary electron emission; Uses of the angular dependencies of the magnetodichroic effect; Applications of the magnetic spectromicroscopy based on the magnetodichroic phenomena.

Studies the fabrication of nanomagnet arrays by shadow deposition on self-organized semiconductor substrates.. Morphology of thee fabrication of nanomagnets; Identification of chains of triangular structures that originate from a step bunch to facet transition occurring at a specific substrate miscut; Longitudinal magneto-optic Kerr effect measurements.