Magnons, Domain Resonances and Elastic Waves in Giant Magneto-Resistive Materials

9701685 Sooryakumar这一更新项目将支持通过非弹性光散射方法研究被超薄间隔层隔开的磁性界面上的交换耦合机制。能够调节斯通纳交换参数的特殊三层结构将允许探测直接控制层间交换的间隔物磁性和电子结构的细节，并提供关于超薄金属薄膜的反铁磁性的信息。域壁激发也将被用来研究微观长度尺度上的层间耦合。此外，还将用光散射方法研究混合价锰氧化物中的强自旋-晶格耦合和电荷-晶格耦合。这一努力将使人们能够研究这些材料中不寻常的、但绝对重要的磁性和结构效应之间的相互作用。这个更新项目将支持对分层结构中的磁性进行激光光谱研究，这些结构可能是下一代磁数据存储和磁电子设备的基础。这项研究的重点是了解被几个原子层隔开的磁性薄膜之间的相互作用，并开发一种实验技术来探测这种相互作用，这种相互作用是其他方法所不能实现的。此外，由于特殊锰氧化物的电阻可以通过磁场调节，这些材料为基于电子自旋的新型器件开辟了新的前景。与这些材料的电子自旋和晶体结构之间的耦合有关的基本物理将用激光散射方法进行研究。***

9701685 Sooryakumar This renewal project will support the study, via inelastic light scattering methods, of exchange coupling mechanisms across magnetic interfaces separated by an ultra thin spacer layer. Special tri-layer structures with the ability to tune the Stoner exchange parameter will allow details of the spacer magnetic and electronic structure that directly controls the inter-layer exchange to be probed and provide information on the antiferromagnetic properties of ultra thin metallic films. Domain wall excitations will also be exploited to study inter-layer coupling over microscopic length scales. In addition, the strong spin-lattice and charge-lattice couplings in the mixed valence manganites will be investigated by light scattering. This effort will allow for the unusual, but decidedly important, interplay between magnetic and structural effects in these materials to be studied. %%% This renewal project will support a laser spectroscopic study of magnetism in layered structures that are likely to underlie the next generation magnetic data storage and magneto-electronic devices. The study focuses on understanding the interaction between magnetic films separated by a few atomic layers and to develop an experimental technique to probe this interaction over length scales not realized by other methods. In addition, since the electrical resistance of special manganite compounds can be tuned by a magnetic field, these materials open new perspectives into novel devices based on the spin of an electron. The underlying physics associated with the coupling between the electron spin and crystal structure of these materials will be investigated by laser light scattering methodologies. ***