Physics Colloquium, September 27, 2005

Dynamics in magnetic micro- and nanostructures

Burkard Hillebrands

Technische Universitaet Kaiserslautern

For applications in sensors and in data storage, the dynamic properties of micro- and nano­structures gain increasing attention. The fundamental excitations in these objects are confined spin waves, and it is useful in particular to understand their properties in view of the noise spectrum in sensor and MRAM applications.

The lecture addresses the dynamics in homogeneously and inhomogeneously magnetized objects starting with an introduction into spin waves and the effects of finite dimensions. In inhomogeneous systems the excitation spectrum is complex, and new phenomena, like localization and tunneling of modes are discussed. The key points are illustrated by results obtained by space- and time-resolved Brillouin-light-scattering technique, which allows one to follow experimentally the propagation of spin wave packets and to present the results in an animated format. To conclude the lecture, the analysis of ultra-high-frequency dynamic properties of small magnetic elements such as squares and rings with spatial resolution in the 300 nanometer range and the potential application to new logic devices based on spin waves are presented.

Dr. Hillebrands' Brief Biography

3.30 p.m., Robert Smith Seminar Room 1080, PRB

Refreshments served at 3:00 p.m., Atrium, PRB