9510434 Giebultowicz The objective of the proposed research is to use neutron diffraction, neutron reflectivity, and synchrotron radiation reflectivity for investigating magnetic and structural properties of novel superlattices composed of mangetic/non-magnetic semiconductors. Most research on artificial magnetic heterostructures and multilayers has been done on metallic systems; experimental and theoretical results for low carrier concentration systems have only recently begun emerging. Studies of such systems are of fundamental importance because the interaction mechanisms underlying their magnetic properties differ from those of metals. Also, heterostructures and multilayers composed of insulating or semiconducting compounds are interesting in that many of these materials are antiferromagnets, frequently having layered structures, thus offering opportunities for "engineering" the superlattices. Systems to be studied will be based primarily on europium and manganese chalcogenides, with samples prepared by molecular beam epitaxy at the Johannes Kepler University, Linz, Austria. Neutron scattering studies will be conducted primarily at the National Institute of Science and Technology, and X-ray measurements at Brookhaven National Laboratory. Complementary measurements of magnetic properties will be made at the Massachusetts Institute of Technology. %%% The objective of the proposed research is to use neutron scattering and synchrotron X-radiation techniques to investigate the magnetic and structural properties of multilayer atomic "superlattices" built up from magnetic and non-magnetic semiconducting materials. Studies of such systems are of fundamental importance because the physical mechanisms by which the atoms in one magnetic layer interact (i.e., communicate) with those in another magnetic layer through an intervening non-magneti c layer are poorly understood and differ significantly from the mechanisms which apply in the case of metallic multilayer superlattices. The materials to be investigated will be based primarily on magnetic europium and manganese selenides and tellurides and non-magnetic lead selenide and telluride. This is a multidisciplinary project, with samples being prepared at the Johannes Kepler University, Linz, Austria, and experimental work carried out at the National Institute of Standards and Technology and at the Brookhaven National Laboratory. In addition, complementary measurements of the magnetic properties will be made at the Massachusetts Institute of Technology. ***
