Numerical Calculation Of Kerr Effect For Magnetic Films

In this thesis the Kerr effect with the incident light wavelength, the incident angle, the number of bilayer and the thickness of magnetic film for Co/Pt MnBi magnetic layered-films and NixSiO2(1-x) (x=0.52, 0.58, 0.65, 0.72 and 0.84) granular films have been calculated. Based on the theory of the equivalent layer, we analyze the effect that the interfacial properties contribute to the whole Kerr effect, such as the interfacial ratio and the orientation of magnetization in the interfacial layer. The results qualitatively help us to understand the interfacial effects. The main content of the thesis can be divided four parts as follows:1 The elementary knowledge of the magneto-optical effect, especially three mechanisms of magneto-optical Kerr effects: polar magneto-optical Kerr effect, longitudinal magneto-optical Kerr effect and transversal magneto-optical Kerr effect, have been introduced. In addition, the principles of magneto-optical recording and erasing, and the recent and future status for magneto-optical recording have been also presented.2 Some theoretical methods for magneto-optical effect, especially, 4×4 matrix method and the theory of the equivalent layer, have been considered.3 Applying 4×4 matrix method, we have calculated the magneto-optical effects as functions of the incident wavelength, the incident angle, the number of layer and the thickness of magnetic layer for Co/Pt, MnBi magnetic layered-films and NixSiO2(1-x) (x=0.52, 0.58, 0.65, 0.72 and 0.84) granular films, as fond in the third, fourth and fifth chapters. It is found that the simulated magneto-optical effects with the incident wavelength agree well with the measured ones. Furthermore, we expand 4×4 matrix method tocalculate the Kerr effects as functions of the number of the layer, the incident angle and the thickness of magnetic layer. It is obvious that the Kerr effects show their maximum at certain incident angle, number of layer or thickness of magnetic layer. For example, for Mn0.53Bi0.47 magnetic multilayered-film system, the Kerr rotation shows its max (7.48 when the thickness of magnetic layer (h) is equal to 12 nm while the Kerr ellipticity appears its max (6.35 when h is equal to 16 nm. The calculated results will be significant for the material design in the future.4 With the 4×4 matrix method and the theory of the equivalent layer, the Kerr effects with the interfacial layer for [Co(0.3nm)/Pt(0.4nm)]X43/Glass(1.21mm) and SiO(237nm)/ MnBi(50nm) / Glass(0.21mm) magnetic multilayered-films have been simulated. It is found that the properties of interfacial layer affect the whole Kerr effect greatly. Comparing the calculated results with the measured ones, we approximately obtain the optimal ratio of the interfacial layer for different magnetic films. For Co/Pt multilayered-film system, the thickness of Co is 0.14nm and the thickness of Pt is 0.05 nm in the optimal interfacial layer. For MnBi multilayered-film system, the thickness of MnBi is 5 nm and the thickness of SiO is 5 nm in the optimal interfacial layer. Based on the optimal interfacial layer, We also calculate the Kerr effects with the thickness of individual layer 0 Furthermore the Kerr effects with the orientation of magnetization in the interfacial layer are calculated. The magnitudes of the Kerr effects decrease with increasing orientation angle.