Micromagnetism and Microstructure of Ferromagnetic Thin Film Systems

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9818296BauerThe goal of this project is the microscopic understanding of (1) the interrelation between the microstructure of ultrathin film systems and their magnetic properties and (2) of the dependence of these properties upon parameters such as film thickness, surfactant, temperature and magnetic field strength, using the novel technique of spin-polarized low energy electron microscopy combined with magneto-optic Kerr effect measurements. The study focuses on the following problems: (i) the influence of grain structure and roughness of the interface and of the clean or adsorbate-covered surface on the magnetic domain structure, (ii) the interlayer coupling between ferromagnetic layers through nonmagnetic or antiferromagnetic spacers, (iii) the influence of the microstructure on the domain wall motion and (iv) the dependence of the domain structure and of the wall motion on the geometry of the magnetic system in submicron dimensions. The results are important not only for the basic understanding of ferromagnetism in reduced dimensions but also for the development and optimization of magnetic recording and sensing devices. %%%In the past all electronic devices were based on the fact that the electron has a charge. In recent years great efforts were made to develop devices which make use of the fact that the electron also has a spin. This has lead already to new high density information storage media and sensors based on ultrathin metallic films. Still higher storage densities and smaller sensors are needed in the next century. To reach this goal the dependence of the properties of spin systems upon their microstructure must be better understood because they are intimately coupled. This can be best achieved using the novel method of spin-polarized low energy electron microscopy which images simultaneously spin distribution and microstructure. The study will not only contribute significantly to the development of the new high technology "spintronics" but at the same time trains students for this economically important field.***