May 12, 2005 , Rock 301, 4:15 PM
Yaroslav Tserkovnyak, Harvard University
Collective Spin Dynamics in Magnetic Nanostructures
Ferromagnetism exhibits exciting novel phenomena when the system size is shrunk to submicron scale. Especially interesting are heterostructures with ferromagnetic and nonmagnetic regions combined in multilayer cake-like structures. I will briefly review the field of mesoscopic magnetoelectronics, where such structures are incorporated in Ohmic circuits, focusing on the scattering- matrix approach. The field received its first significant boost with the experimental discovery of giant magnetoresistance, some 20 years ago. Ten years later, theoretical prediction of current- driven magnetic instabilities, with subsequent experimental confirmation, ignited interest in ferromagnetic dynamics in hybrid nanostructures. Since then, many aspects of magnetization dynamics, such as current-driven reversal, stable precessional states, spin pumping, microwave emission, low- and high-frequency magnetization noise have been extensively explored. A large body of fascinating experiments offer a broad basis for theoretical exploration, but the number of open questions has only been growing in recent years. I will describe several insightful experiments, discuss theoretical progress in understanding nanomagnet dynamics, and briefly discuss some theoretical proposals for spintronic applications.
Host: Harsh Mathur