The Metal-Nonmetal Transition in Magnetic Local Moment Systems

局部磁矩系统中的金属-非金属转变

• 批准号: 9802126
• 负责人: Peter Dowben
• 金额: $ 33.01万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9802126&HistoricalAwards=false
• 关键词: Metal; Nonmetal; Transition; Magnetic; Local

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. ***

9802126 Dowben这是一个集中的研究小组建议，涉及三名具有互补实验技能的主要研究人员。 该研究研究了锰氧化物和稀土pnictnides（氮化物）的表面电子和结构特性。这些引起极大兴趣的材料是因为它们具有非金属过渡到金属转变的铁磁过渡。 但是，磁性行为与电运输特性之间的关系现在已经充分了解。该程序的目标是了解非金值转换附近的非金属向金属过渡的性质，并研究表面铁磁特性和金属上的表面特性与这些材料中的批量特性可能有所不同。该计划将解决重要问题，例如表面磁性是否精确遵循散装材料的磁性。 该程序采用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带结构，批量传输特性以及磁性。尽管这是基本研究计划，但该项目的结果将与磁性和超导性的一般领域有关。 例如，氧化物材料的表面磁和运输特性是信息存储技术领域的基本问题。 %%％这是一个集中的研究小组建议，涉及三名具有互补实验技能的主要研究人员。 该研究涉及氧化锰和稀土氮化物材料的表面与块状特性之间的关系。在这些材料中，磁性特性的快速变化可以同时发生，而电导率的变化很大。 但是，这两种现象之间的关系尚不清楚。此外，材料的表面特性与批量特性之间的关系也是一个开放的问题。 这项工作将结合一系列的表面光谱和结构技术，以获取有关这些材料的磁性和传输特性的新信息。与内布拉斯加州的理论家进行密切合作 - 奥马哈，内布拉斯加州 - 林肯和南达科他州矿业学校，案例西部保护区U将促进对测量的解释。尽管这是基本研究计划，但该项目的结果将与磁性和超导性的一般领域有关。 例如，氧化物材料的表面磁和运输特性是信息存储技术领域的基本问题。 ***