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.
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Host: Einstein
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