| In the last twenty years, extensive studies have been made on the structure, basic magnetic properties, interlayer coupling, interfacial structures and its relative effects in magnetic thin and ultrathin films due to their potential application in magnetic random access memory ( MRAM) and ultrahigh-density data storage. In addition, patterned thin films with micron and submicron array, close to the sizes in applications, have recently attracted increasing interest because of their different behaviors from the continuous thin films. In this thesis, mainly by FMR, combined with MOKE and magnetic measurement, systematical studies have been made on the magnetic properties, especially magnetic anisotropy in epitaxial single crystalline Fe ultathin films on GaAs and InAs substrates in polycrystalline thin films and in polycrystalline NiFe and NiFeCo patterned films of micron and submicron rectangular elements arrays. The major results are summariaed as follows:I. An investigations of magnetic properties in epitaxial single crystalline Fe ultathin films.1. MOKE and FMR studies were performed on single crystalline Fe ultathin films epitaxially grown on III-V semiconductor GaAs substrate with thickness 4.1-33 monolayer (ML). A theoretical mode for fitting FMR experimental data was established. The results demonstrated the structures and reproduced the evolution of the magnetic properties of ultrathin films with various thickness from the state of superparamagnetic nano-cluster through coexistence of two magnetic phases to continuous film, especially the change of magnetic crystalline anisotropy from unixial to cubic. The parameters such as effective magnetization, gyromagnetic ratio, g value and various anisotropy constant were determined by theoretical fitting. The major findings are listed below:(1) The film of 4.1 ML consists of superparamagnetic nano-cluster with large perpendicular anisotropy and in-plane uniaxial anisotropy. The oscillatory curve of is symmetrical which can be described by a function of sin square.(2) FMR data show that the film of 5.2 ML has two magnetic phases, implying a transition state from superparamagnetic nano-cluster structure to continuous film.(3) Films thicker than 8.4 ML form continuous films. The perpendicular anisotropy and in-plane uniaxial anisotropy decrease with increasing film thickness. The oscillatory curve of Hres is asymmetrical, which requires an additional term of anisotropy with four-fold symmetry to fit. The anisotropy of four-fold symmetry indicates the appearance of cubic anisotropy.(4) The in-plane unixial anisotropy existed in films originates probably from magneto-elastic interaction due to the anisotropic strain caused by lattice mismatch at the interface.(5) g value of films keeps approximately a constant value 2.08 similar to bulk Fe. 2. MOKE and FMR studies were performed on epitaxial single crystalline FePh.D Thesis; Investigations of magnetic properties on magnetic thin, ultrathin and patterned filmsultathin films on III-V semiconductor InAs substrate with thickness of 8-25monolayer (ML). The major findings are listed below:(1) The in-plane magnetic crystalline anisotropy of film with 8-25 ML thick are four-fold anisotropy, and the in-plane unixial anisotropy of Fe/InAs films decreses faster with thickness than that in Fe/GaAs films. It could be explained that the stain relaxation of Fe/InAs films is also faster than that in Fe/GaAs films as indicated by LEED.(2) The oscillatory curve of Hres is asymmetrical for films. It originates mainly from the lower resonance field Hres comparing with anisotropy field, which causes deviation of the direction of magnetic field from that of magnetization.(3) By fitting, g value of films keeps approximately a constant value 2.08 similar to that of Fe/GaAs films and bulk Fe.II. Investigations of magnetic properties in polycrystalline NiFe single-layer and NiFeCo sandwich unpatterned and patterned films.1. There are abnormal changes in the magne...
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