5 µm

1. SGER: Spin-Transfer-Torque Devices Based on Magnetostatically-Coupled Sub-50nm StructuresCaroline A. Ross, Massachusetts Institute of Technology, DMR 0849278 This project develops magnetic structures for data storage and manipulation based on spin-torque effects. We have focussed on understanding current-induced switching of magnetic nanostructures, on measuring high frequency magnetic behavior, including giant magnetoimpedance (GMI), as well as on developing fabrication methods for magnetic nanostructures. We analysed current-driven domain wall motion in magnetic wires and multilayers, and designed a logic device based on domain wall motion. We investigated the GMI of exchange-biased films, showing that a linear response could be obtained at zero field, useful in making a low-field sensor. We also developed methods for fabricating magnetic dots and wires based on block copolymer self-assembly. 5 µm Design for device, and prototype of the write element, consisting of a NiFe wire with IrMn exchange bias tabs.

2. SGER: Spin-Transfer-Torque Devices Based on Magnetostatically-Coupled Sub-50nm StructuresCaroline A. Ross, Massachusetts Institute of Technology, DMR 0849278 We hosted a Chilean student, Juan Florez, who has continued to work on this project and who will return with a postdoctoral fellowship next year. Carlos Garcia,a postdoc who worked on the project, has accepted a faculty position in Istanbul. Prof. Mohammed Britel, Tangier, Morocco, visited to work on high frequency measurements. We gave presentations at a Teachers summer program and had an MIT undergraduate to work on film deposition and measurement. The knowledge gained on high frequency behavior has been broadened into other projects such as our NSF-supported Materials World Network project. Our classes on magnetism are available on the MIT OpenCourseWare site. Theory gives a good match to the experimental data on giant magnetoimpedance. From JM Florez.