Structural, Magnetic and Electronic Properties of Interstitially Modified Magnetic Systems

9705136巴尼克这是一个更新项目，旨在研究Sm2Fe17及其相关结构的气相元素间隙改性效果。这种改性为开发具有潜在适用于永磁体应用的性能的新型磁性材料展示了希望。在拟议的研究中，将讨论有关间隙R2Fe17(N，C，H)x(R=稀土元素)和替代Sm2Fe17-Yty(T=Ga，Al和Si)的一般问题，以及相关的R(Fe，T)12，R3(Fe，T)29和R2Fe14B稀土体系。将通过核磁共振、穆斯堡尔效应、X射线吸收精细结构、中子衍射和Muon自旋来探索这种局域的原子、电子和磁结构以及相关的宏观磁性。我们的目标是了解导致磁各向异性和单个亚晶格磁化强度变化的特定局部方面，以及确定特定位置矩对局部环境和晶格膨胀的依赖关系。%这是一项研究Sm2Fe17及其相关结构的气相元素间隙改性效果的更新项目。永磁体对国家安全和商业行业都具有重要意义。例如，一辆汽车包含100多个磁性部件。永磁体的总市场目前每年超过100亿美元，而且还在迅速增长。这种应用要求材料具有高性能、高工作温度、低成本等特点。自20世纪80年代以来，寻找(取代钴的)永磁材料的工作主要集中在铁基化合物上，因为铁资源丰富，价格低廉，并且具有相对较高的磁矩。最近，人们发现，当氮等气态元素扩散到选定的铁化合物中时，磁性会大大增强。我们的研究计划利用磁共振等微观实验技术来研究这种插入元素不仅在改善材料的磁性方面所起的作用，而且在改善材料的一般物理性质方面发挥的作用。***

w:\awards\awards97\budnick05136.doc 9705136 Budnick This is a renewal project to study the effect of gas-phase- element interstitial modification of Sm2Fe17 and related structures. Such modification is showing promise for the development of in a new class of magnetic materials with properties potentially suitable for permanent magnet applications. In the proposed research, general questions concerning both interstitial R2Fe17(N,C,H)x (R = rare-earth element) and substitutional Sm2Fe17-yTy (T = Ga, Al, and Si), as well as the related R(Fe,T)12, R3(Fe,T)29, and R2Fe14B rare-earth systems, will be addressed. The local atomic, electronic, and magnetic structures, and the related macroscopic magnetic properties will be explored by nuclear magnetic resonance, Mssbauer effect, x-ray absorption fine structure, neutron diffraction, and muon spin rotation. The goals are to understand the specific local aspects leading to changes in magnetic anisotropy and individual sublattice magnetization as well as to determine the specific site moment dependence on local environment and lattice expansion. %%% This is a renewal project to study the effect of gas-phase- element interstitial modification of Sm2Fe17 and related structures Permanent magnetic magnets are vital for both national security as well as commercial industries. For example, an automobile contains more than 100 magnetic components. The total market for permanent magnets is currently more than $10 billion per year, and growing rapidly. This application requires materials with high performance, high working temperature, and low cost. Since the 1980s, the search for permanent magnetic materials (to replace cobalt) has concentrated on iron-based compounds because iron is abundant, inexpensive, and has relatively high magneti c moment. Recently, it has been discovered that when gaseous elements such as nitrogen are diffused into selected iron compounds, the magnetic properties are greatly enhanced. Our research program utilizes microscopic experimental techniques such as magnetic resonance to study the role that such inserted elements play in improving not only the magnetic properties, but the general physical properties of materials. ***