With spin toward efficient electronics
Exploring the secrets of spin phenomena for novel electronic components
Spin is the intrinsic angular momentum of the electron. Among other things, it is responsible for magnetism. Magnetic phenomena currently play a major role in many areas of information technology. Magnetic layers serve as media for data storage. Magnetic read heads are found in hard disk drives of conventional computers and laptops. If electronic components are to become more energy-saving, and at the same time the data density and data processing speed are to be increased, there is no way around nanophysics.
For particularly efficient electronics, the aim is to use not only the electrical charge of electrons but also their spin as information carrier. This new type of information processing is called spin electronics, or spintronics for short. Our team specializes in sophisticated spectroscopic techniques for analysing the spin of electrons. We are on the track of phenomena which can help to exploit the microscopic properties of spin on the macroscopic scale. As a result, this opens up ways of developing new applications in data processing.
The spin in extremely thin layers
The electron spin can also play an important part in non-magnetic materials. The current focus of interest is on surface alloys in which heavy elements such as bismuth, thallium or lead are embedded in the topmost atomic layer of metals such as copper or gold or semiconductors such as silicon or germanium. In these cases, the electrons feel that there is a solid on one side and a vacuum on the other. This can result in the alignment of the electron spin, linked directly with the direction of the electric current. Such a property is promising for applications in the field of spintronics.
Preparing the electron spin
Experiments with spin-aligned electrons allow direct insight into the spin-dependent microscopic properties of magnetic and non-magnetic systems. Either spin-aligned electrons are used as projectiles or the spin direction is detected of the electrons which are emitted from the material sample with the aid of light. Both types of experiment are very elaborate and are therefore carried out by only a few teams worldwide.
Our analytical methods are extended by scientific techniques which investigate the precise chemical composition of the samples. We are also able to clarify precisely the crystallographic order and the magnetic properties. In our research and experiments, we work closely together with other research groups at home and abroad, for example with the University of Halle-Wittenberg and the University of Hiroshima in Japan. Funding for the wide-ranging work is provided by the German Research Foundation, among others.