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

这个更新项目将支持通过非弹性光散射方法研究由超薄间隔层分隔的磁界面上的交换耦合机制。具有调整斯通纳交换参数能力的特殊三层结构将允许对直接控制层间交换的间隔磁和电子结构的细节进行探测，并提供超薄金属薄膜反铁磁特性的信息。畴壁激发也将用于研究微观长度尺度上的层间耦合。此外，我们还将利用光散射的方法研究混合价态锰的强自旋晶格耦合和电荷晶格耦合。这一努力将使这些材料的磁性和结构效应之间的不寻常的、但绝对重要的相互作用得以研究。该更新项目将支持层状结构中磁性的激光光谱研究，这可能是下一代磁性数据存储和磁电子设备的基础。本研究的重点是了解被几个原子层分隔的磁膜之间的相互作用，并开发一种实验技术来探测这种相互作用在其他方法无法实现的长度尺度上的相互作用。此外，由于特殊锰矿化合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视角。这些材料的电子自旋和晶体结构之间耦合的基本物理将通过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. ***