International Research Fellowship Program: Research on Local-Moment Ferromagnets: Spin-Dependent Electronic States of the Bulk and Surface and Within Ultrathin Films

Correa Juliet S, Ventura CA

Investigators

Abstract

The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will provide twenty-four months of support for research by Dr. Juliet S. Correa to work with Dr. Markus Donath at the Westfalische Wilhelms-Universitat Munster in Germany. Support for this project is from the Math and Physical Sciences Directorate's Office of Multidisciplinary Activites. Dr. Correa is researching local-moment ferromagnets, looking specifically at the spin-dependent electronic states of the bulk and surface and within ultrathin films. The first of two projects involves researching the spin polarization of the surface of NiMnSb (Nickel Manganese Antimonide) thin films and bulk single crystals. The second is determining the sort of magnetism that occurs at the surface of the rare earth magnet Gadolinium. Experiments are carried out using a state of the art ultra-high-vacuum system wherein the thin films can be prepared (by epitaxial growth, sputtering and annealing) and studied in a wide variety of ways (crystal quality, surface chemistry, occupied/unoccupied states, and STM) without breaking vacuum. Such constant environmental conditions will likely yield clear and reliable results, and eliminate some of the confusion that currently exists in the field of surface-magnetic measurements. Dr. Correa's first work has involved making angle resolved and spin-polarized occupied states measurements, a first of their kind on single crystal NiMnSb thin films. Dr. Donath is a professor at the Westfalische Wilhelms-Universitat Munster and a recognized international expert in the field of surface magnetism.