Perpendicular-Current Spin-Polarized Transport Studies at Low Temperatures

Michigan State University, East Lansing MI

Investigators

Abstract

Science and technology are driving attempts to understand the physics underlying spin-polarized transport in metallic magnetic multilayers. Such understanding can usually be achieved most directly in the geometry with current flow perpendicular (CPP) to the metallic layers, pioneered by the Michigan State University group. Novel experiments will be performed to address the following questions: (1) What is the source of unexpectedly large spin-flipping found at certain non-magnetic/non-magnetic metal interfaces? (2) What are the resistances and dynamics of individual magnetic domain walls and vortices? (3) What is the importance of interfacial roughness on the CPP magnetoresistances of Fe/Cr multilayers? (4) How far can a polarized current penetrate into a superconductor? (5) Can a predicted magnetic analog of the AC Josephson effect be observed? This research will play an important role in educating BS, MS, and PhD students, including women and minorities. An outreach component of this program involves supervision of the physics portion of the Michigan Science Olympiad. In one decade, Giant Magnetoresistance in metallic magnetic multilayers has moved from discovery to marketed devices, such as read heads for high-density computer disk drives. But further progress requires still larger magnetoresistance and still smaller detectors. A candidate for the next generation of detectors is Giant Magnetorisistance multilayers measured with current flow perpendicular to the layers, a geometry pioneered by the group at Michigan State University. This geometry promises larger magnetoresistance in smaller samples. But both fundamental and practical issues still need to be resolved. This research program will address several such issues in novel ways, and will involve BS, MS, and PhD students, including women and minorities. The students will learn how to pose significant scientific questions, assemble state-of-the-art equipment to address them, and analyze data obtained with the equipment.