Magnetization Manipulation in Nanostructures by Spin Currents

Stanford University, Stanford CA

Investigators

Abstract

This individual investigator award supports a project that will investigate the ultra-fast manipulation of the magnetization in nanostructures by spin currents. In particular, the work explores novel opportunities to manipulate the magnetization on the nanometer length scale and picosecond time scale, based on utilization of the strong, short range quantum mechanical exchange interaction. The project involves sample preparation, sample characterization, and direct imaging of the time dependent magnetization by photoemission electron microscopy (PEEM) measurements. Magnetic images will be recorded by pump-probe techniques using magnetic excitations triggered by picosecond spin current pulses produced by an optical switch and 50 ps x-ray probe pulses from the Advanced Light Source in Berkeley. Such measurements promise scientific breakthroughs in this scientifically and technologically exciting area. The ability to manipulate the magnetization on these time and length scales will have a strong impact in the field of high density magnetic storage and in the emerging area of spintronics. Both are areas of importance for future growth in information technology. The research will be carried out mainly by a Stanford graduate student and postdoctoral research associate. It involves work at Stanford University and at the near-by Lawrence Berkeley National Laboratory and the IBM Almaden Research Center. The interactive character of the work involving a University, a National Laboratory and an industrial laboratory will be of great educational value for the young scientists involved. Today, all magnetic devices ranging from "low tech" transformers to "high tech" magnetic storage devices are switched by long-range magnetic fields that surround wires or coils through which a current is passed. This individual investigator award supports a project that investigates a completely new approach that is superior for the smaller and faster magnetic devices that underlie tomorrow's technology of storing or processing information in computers. The new idea is to switch a small magnetic area or "bit" by an injected spin current, relying on the strong, short range quantum mechanical exchange interaction. The goal of the work is to directly image, through ultrafast snapshots, how the magnetization of a small magnetic area is switched by the injected spin current. These images will be recorded with synchrotron x-ray pulses at the Advanced Light Source in Berkeley and they may lead to improved methods of storing and processing information. Because the work requires sophisticated sample preparation and measurements it utilizes facilities at Stanford University, the near-by Lawrence Berkeley National Laboratory and the IBM Almaden Research Center. The interactive character of the work involving a University, a National Laboratory and an industrial laboratory will be of great educational value for the young scientists involved.