Neutron and Synchrotron Radiation Scattering Studies of Multilayered Structures Based on Europium Chalcogenides and other Magnetic Semiconductors

9510434吉布尔托维奇拟议的研究目的是利用中子衍射、中子反射率和同步辐射反射率来研究由磁性/非磁性半导体组成的新型超晶格的磁性和结构性质。大多数人工磁性异质结构和多层膜的研究都是在金属系统上进行的，对于低载流子浓度系统的实验和理论结果直到最近才开始出现。对这类体系的研究具有重要意义，因为它们的磁性与金属的相互作用机制不同。此外，由绝缘或半导体化合物组成的异质结构和多层膜也很有趣，因为这些材料中的许多都是反铁磁体，经常具有层状结构，因此为超晶格的工程提供了机会。将要研究的系统将主要基于Eu和锰硫化物，样品由奥地利林茨约翰尼斯开普勒大学的分子束外延制备。中子散射研究将主要在国家科学技术研究所进行，X射线测量将在布鲁克海文国家实验室进行。麻省理工学院将对磁性进行补充测量。这项研究的目的是利用中子散射和同步辐射技术来研究由磁性和非磁性半导体材料构成的多层原子“超晶格”的磁性和结构性质。对这类系统的研究具有基本的重要性，因为一个磁层中的原子通过中间的非磁层与另一个磁层中的原子相互作用(即，通信)的物理机制鲜为人知，并且与适用于金属多层超晶格的机制有很大的不同。要研究的材料将主要以磁性的铕、锰、硒和碲化物以及非磁性的硒和碲的铅和碲为基础。这是一个多学科项目，奥地利林茨的约翰尼斯·开普勒大学正在准备样品，国家标准与技术研究所和布鲁克海文国家实验室进行了实验工作。此外，麻省理工学院将对磁性进行补充测量。***

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. ***