Speaker:Professor Ralph Skomski

University of Nebraska-Lincoln

Title: Basic Rare Earth Quantum Mechanics

Bio:  The research of Ralph Skomski focuses on theory of magnetic nanostructures. The main aim is to model the behavior of nanostructures and to make predictions about conceivable but difficult-to-produce materials.

The relevant length scales of the involved structural features vary from a few interatomic distances to more than 100 nm, and each length scale has its own characteristics. Examples of small-scale magnetic nanostructures of interest are nanotubes, nanorings, patterned thin films, and particulate materials. These structures exhibit, among other features, interesting spin-wave and magnetization-reversal modes. On an atomic scale, chemical substitutions, interstitial modification, and changes in the crystal structure are exploited to tailor intrinsic properties such as anisotropy, Curie temperature and magnetic moment.

On length scales larger than a few nm, the magnetic material can be treated as a continuum. In this regime, the atomic properties enter the consideration as micromagnetic parameters. The morphological peculiarities of magnetic nanostructures lead to a variety of novel micromagnetic effects. One example is intergranular exchange coupling, which has a strong effect on the performance of advanced permanent magnets, magnetic recording media, and magnetoresistive materials.

Other research areas of interest are time-dependent magnetization processes (magnetic viscosity and fast processes), the spin structure of half-metallic ferromagnets as well as topics such as RKKY interactions between nanomagnets embedded in a nonmagnetic metallic matrix. Emphasis is on analytic models, which are designed to complement and guide other scientists' numerical approaches, such as band-structure calculations.