The Metal-Nonmetal Transition in Magnetic Local Moment Systems

9802126道本这是一个协作的重点研究小组提案，由三名具有互补实验技能的首席研究人员参与。研究了锰氧化物和稀土氮化物(氮化物)的表面电子结构性质。这些材料引起了人们的极大兴趣，因为它们的铁磁转变似乎伴随着非金属到金属的转变。然而，磁行为和电传输特性之间的关系现在已经被很好地理解了。该计划的目标是了解铁磁转变附近非金属到金属转变的性质，并研究这些材料的表面铁磁性质和金属性质如何与体相性质不同。该计划将解决重要的问题，如表面磁性是否准确地跟随块体材料的磁性。该程序使用了大量的光谱技术和表征工具来阐明氧化物和氮化物材料的电子能带结构、体输运性质和磁性。虽然这是一个基础研究项目，但该项目的结果将与磁学和超导的一般领域相关。例如，氧化物材料的表面磁性和输运性质是信息存储技术领域的基本问题。%这是一个协作的重点研究小组提案，由三名具有互补实验技能的主要研究人员参与。研究了氧化锰和稀土氮化物材料的表面性质和体相性质之间的关系。在这些材料中，磁性的快速变化可以与电导率的大变化同时发生。然而，这两种现象之间的关系还没有得到很好的理解。此外，材料的表面性质和块体性质之间的关系也是一个悬而未决的问题。这项工作将结合一系列表面光谱和结构技术，以获得关于这些材料的磁性和传输性质的新信息。与内布拉斯加州-奥马哈大学、内布拉斯加州-林肯大学、南达科他州矿业学院和凯斯西储大学的理论家密切合作，将促进对测量结果的解释。虽然这是一个基础研究项目，但该项目的结果将与磁学和超导的一般领域相关。例如，氧化物材料的表面磁性和输运性质是信息存储技术领域的基本问题。***

9802126 Dowben This is a collaborative focused research group proposal involving three principal investigators with complementary experimental skills. The research investigates the surface electronic and structural properties of manganese oxides and rare earth pnictnides (nitrides). These materials of considerable interest because they have a ferromagnetic transition that appears to accompany the non-metal to metal transition. However, the relation between the magnetic behavior and the electrical transport properties is now well understood. The goals of the program are to understand the nature of the non-metal to metal transition near the ferromagnetic transition, and to investigate how the surface ferromagnetic properties and metallically may differ from the bulk properties in these materials. The program will address important issues such a whether the surface magnetism precisely follows that of the bulk material. The program employs a large number of spectroscopic techniques and characterization tools to elucidate the electronic band structure, bulk transport properties and magnetic properties of the oxide and nitride materials. While this is fundamental research program the results of the project will be relevant to the general fields of magnetism and superconductivity. For example, surface magnetism and transport properties of oxide materials are fundamental issues in the field of information storage technology. %%% This is a collaborative focused research group proposal involving three principal investigators with complementary experimental skills. The research deals with the relationship between the surface and bulk properties of manganese oxide and rare earth nitride materials. In these materials, rapid changes in magnetic properties can occur simultaneously with large changes in the electrical conductivity are ob served. However, the relation between these two phenomena is not well understood. Further, the relation between the surface properties of the materials and the bulk properties is also an open question. This effort will combine a range of surface spectroscopic and structural techniques to obtain new information about magnetic and transport properties of these materials. Close collaboration with theorists at U Nebraska - Omaha, U Nebraska - Lincoln, and South Dakota School of Mines, and Case Western Reserve U will facilitate interpretation of the measurements. While this is fundamental research program the results of the project will be relevant to the general fields of magnetism and superconductivity. For example, surface magnetism and transport properties of oxide materials are fundamental issues in the field of information storage technology. ***