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

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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.***