Neutron Scattering Studies of Magnetic Semiconductors and their Superlattices

本研究的目的是利用中子散射技术研究立方碲化锰和硒化锰及其多层和合金中的磁有序和磁相互作用。这些材料不是自然产生的，但可以通过分子束外延（MBE）在该晶体相中制造，因为它们的锰亚晶格构成了受短程相互作用支配的受挫海森堡反铁磁体，因此具有很大的基础兴趣。MBE提供了以可控的方式变化各种自由度的机会，这些自由度直接影响它们的磁性行为，如应变、磁层分离、稀释和维度，从而接触到磁学中各种根本性的新问题。这项研究将着重于研究磁层之间的耦合，以了解锰-锰相互作用的性质和范围，而不仅仅是那些涉及最近邻的相互作用。新的中子散射实验将开始，使用这些材料的超薄层，努力观察从三维到二维的交叉，并最终研究二维极限本身的磁相互作用。样品将在圣母大学制备，中子散射实验将主要在密苏里大学研究反应堆进行。本研究的目的是利用中子散射技术研究立方碲化锰和硒化锰薄层以及多层及其合金中的磁有序和磁相互作用。这些材料不是自然产生的，但可以通过分子束外延（MBE）以这种结构形式生长，因为锰离子形成“受挫d”反铁磁结构，由离子之间的短程相互作用控制。生长技术允许控制直接影响磁性行为的因素的变化，如应变、磁性层的分离、磁性离子的稀释等，从而提供了一系列磁学中根本性的新问题。这项研究将着重于研究磁性层之间的耦合，以了解锰离子之间相互作用的性质和范围。新的中子散射实验将开始，利用这些材料的超薄层，努力观察从三维到二维的交叉磁性行为。样品将在圣母大学制备，中子散射实验将主要在密苏里大学研究反应堆进行。＊＊＊

9510241 Furdyna The objective of the proposed research is to investigate magnetic ordering and magnetic interactions in cubic manganese telluride and manganese selenide, as well as in their multilayers and alloys, by means of neutron scattering techniques. These materials, which do not occur naturally but can be fabricated in this crystal phase by molecular beam epitaxy (MBE), hold great fundamental interest because their manganese sublattices consititute frustrated Heisenberg antiferromagnets governed by short-range interactions. MBE provides the opportunity to vary in a controlled fashion various degrees of freedom which directly affect their magnetic behavior, such as strain, magnetic layer separation, dilution, and dimensionality, thus accessing a variety of fundamentally new problems in magnetism. The research will focus strongly on investigating the coupling between magnetic layers in order to understand the nature and range of manganese-manganese interactions beyond those involving nearest neighbors. New neutron scattering experiments will be initiated, using ultrathin layers of these materials, in an effort to observe the crossover from three to two dimensions, and ultimately to investigate magnetic interactions in the two-dimensional limit itself. Samples will be prepared at Notre Dame University, and the neutron scattering experiments will be conducted primarily at the Missouri University Research Reactor. %%% The objective of the proposed research is to investigate magnetic ordering and magnetic interactions in thin layers of cubic manganese telluride and manganese selenide, as well as in multilayers and alloys thereof, using neutron scattering techniques. These materials, which do not occur naturally but can be grown in this structural form by molecular beam epitaxy (MBE) hold great fundamental interest because the manganese ions form "frustrate d" antiferromagnetic structures governed by short-range interactions between the ions. The growth technique permits the controlled variation of factors that directly affect the magnetic behavior, such as strain, separation of the magnetic layers, dilution of the magnetic ions, etc., thereby providing access to a range of fundamentally new problems in magnetism. The research will focus strongly on investigating the coupling between magnetic layers in order to understand the nature and range of interactions between the manganese ions. New neutron scattering experiments will be initiated, using ultrathin layers of these materials, in an effort to observe the crossover from three to two dimensional magnetic behavior. Samples will be prepared at Notre Dame University, and the neutron scattering experiments will be conducted primarily at the Missouri University Research Reactor. ***