Condensed Matter Physics Seminar

2 p.m., Thursday, October 31, 2002
Room 1201, Physics Building

 Transport of Spin in Multilayer Films

Mark Stiles

(NIST Gaithersburg)

Abstract:  Devices in which the electron spin as well as its charge influence the transport are becoming important in device applications. For example, commercial magnetic field sensors and read heads for magnetic disk drives are based on magnetic multilayers that exhibit the giant magnetoresistance effect. Magnetic multilayers consist of magnetic thin films separated by non-magnetic thin films. The giant magnetoresistance is the change in resistance that occurs when the relative alignment of the magnetization of two layers is changed by a magnetic field. The change occurs because the magnetic layers spin polarize the current in the non-magnetic layers. Recently it has been shown that not only can the magnetic configuration affect the spin-polarized current, but the spin-polarized current can affect the magnetic configuration. When the spin-polarized current is large enough, it can reverse the magnetization of one of the layers. This effect is being studied as a possible way to switch magnetic memories. In this talk, I will describe giant magnetoresistance and spin transfer torques, review the important experiments, and describe simple models of these phenomena. These models emphasize the importance of interface effects.
Host:  Einstein
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