Lars Bommer

Magnetische und strukturelle Eigenschaften von NdFeB und Co Nanostrukturen auf unterschiedlichen Zeitskalen Lars Bommer

One of the greatest achievements in modern science is the development of highly specialized magnetic materials which in different forms can be found in a variety of applications. Especially strong permanent magnets like NdFeB and SmCo, which constitute basic parts in electric motors, speakers, bearings and, of course, in magnetic data storage or magnetic nanoparticles and suspensions like e.g. ferro-fluids which in medicine are successfully used for cancer detection and treatment. A new field of application, that becomes increasingly important are so-called microelectromechanical devices (MEMS). They are miniaturized systems like sen-sors and actors, deposited on a chip or substrate fulfilling special functions. With ongoing miniaturization of such systems, the development of magnets is needed that provide defined properties even at smallest dimensions. Depending on the field of application high remanence, saturation or coercive field values are de-sired. Beneath that long durability, preservation of the magnetic properties even after many magnetization reversals is needed. For applications with short switch-ing times, e.g. in data storage technology, one has to take the magnetodynamic properties into account. Therefore the present work deals with the production of highly miniaturized magnetic systems and the characterization of their magnetic and microstructural properties on long (quasistatic) and ultra short timescales. The developed con-cepts and knowledge can later be of importance in developing and improving new magnetic materials.