An Introduction to Spin Transport in Nanoscale
Metallic Devices

Michael J. Erickson '04
School of Physics and Astronomy
University of Minnesota

Spin transport electronics, or Spintronics, is a field of study at the interface of charge based computing and magnetic storage.  The fact that electrons have both charge (electronics) and an intrinsic spin (magnetism) has been employed in tandem providing devices with unique behavior, some having already achieved widespread commercial application.  Electronic devices utilizing electron spin have broad applications as magnetic field sensors, spin-based transistors, magnetic random access memories and a variety of other technologies with many potential applications currently in research and development.  The fundamental usefulness of these devices is derived from the ability to manipulate the spin of the electron in addition to the charge.  Although much is already known about charge transport in metals, significantly less is known about the properties of diffusing spins.  For this reason, spin-dependent transport experiments involving the injection of spins from a ferromagnetic injector (FM), which provides a source of polarized spins, into a non-magnetic material (N) and the subsequent detection by a second ferromagnetic detector are key to the development of future Spintronic devices.  In this talk I will describe how we use the diffusion of spins in metallic nanostructures with a lateral geometry to ascertain a variety of important characteristics of spin transport.  By altering the length of these devices (i.e., how far the spins must travel), applied magnetic field, temperature and the materials used allows for the measurement of spin lifetimes, scattering mechanisms, and injection efficiencies which are independent of the electron charge current.  Our experiments on metallic nanoscale devices demonstrate that material properties in combination with interface effects strongly influence spin injection and relaxation within the devices.  These results are of great importance towards the development of novel Spintronic devices for scientific and technological applications.