Structure-Property Relationships in Colossal Magnetoresistance Thin Film Materials through Nanofabrication

该项目旨在通过纳米制造和表征，更好地了解一类被称为“巨”磁阻（CMR）材料的铁磁立方钙钛矿材料中的自旋、电荷和晶格耦合。该项目还强调在本科和研究生两级发展综合研究和教育机会。（La,Sr）MnO3等铁磁立方钙钛矿材料的磁阻响应对晶格应变和结构畸变极为敏感。将结构畸变与磁性和电子性质联系起来，对于揭示观测到的异常大磁阻效应的起源尤为重要。本项目专门研究(i)局部磁结构与几何约束下应变状态之间的关系，以及（ii）亚微米尺寸器件异质结构中的磁输运。CMR材料的应变状态可以通过纳米加工的几何约束来定制，所得到的纳米结构将被磁性和电子学表征。这种方法不仅提供了这些材料中异常大磁阻背后的结构和磁性之间相互作用的信息，而且还提供了随着磁性介质变得更密集，它们纳入磁记录应用的基本量子限制。该项目涉及具有高潜在技术相关性的材料科学主题领域的基础研究问题。该研究将在基础层面上为磁性器件的新领域贡献基础材料科学知识。从研究中获得的基本知识和理解有望通过为设计和生产改进的材料和材料组合提供基本的理解和基础，从而有助于提高先进设备的性能和稳定性。该计划的一个重要特点是通过在基础和技术重要领域培养学生，将研究和教育相结合

This project seeks greater understanding of the spin, charge and lattice coupling in a class of ferromagnetic cubic perovskite materials known as "colossal" magnetoresistance (CMR) materials through nanofabrication and characterization. The project also emphasizes the development of integrated research and educational opportunities at both the undergraduate and graduate levels. The magnetoresistive response of ferromagnetic cubic perovskite materials such as (La,Sr)MnO3 is extremely sensitive to lattice strain and thus to structural distortion. Correlating structural distortions with magnetic and electronic properties is particularly important in shedding light on the origin of the anomalously large magnetoresistance effect observed. This project specifically addresses (i) the relationship between local magnetic structure and the strain state through geometrical confinement and (ii) the magnetotransport in submicron size device heterostructures. The strain state of CMR materials can be tailored by geometrical confinement through nanofabrication and the resulting nanostructures will be characterized magnetically and electronically. This approach provides information not only on the interplay between structure and magnetics behind the anomalously large magnetoresistance in these materials but also on the fundamental quantum limit of their incorporation into magnetic recording applications as magnetic media become denser.%%%The project addresses basic research issues in a topical area of materials science having high potential technological relevance. The research will contribute basic materials science knowledge at a fundamental level to new aspects of magnetic devices. The basic knowledge and understanding gained from the research is expected to contribute to improving the perform-ance and stability of advanced devices by providing a fundamental understanding and a basis for designing and producing improved materials, and materials combinations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area.***