Spin-transfer phenomena in high-anisotropy magnetic nanostructures

Prof. Eric Fullerton
University of California, San Diego

Abstract
In most magnetic applications the orientations of the magnetic elements are controlled by external magnetic fields.  However, it has recently been appreciated that the relative orientations of nano-magnets can be controlled directly by the injection of spin polarized currents known as spin transfer effects.  The ability of a spin-polarized current to reverse the magnetization orientation of a nanomagnets should enable a range of devices such as high performance random-access magnetic memories and spin-oscillators [1].  In this presentation I will review the basic properties of spin-transfer and highlight recent research on spin-transfer effects in nano-elements having strong perpendicular magnetic anisotropy [2,3].  This perpendicular geometry has a number of advantages including efficient coupling of the spin-current to magnetic excitations, narrow (<10 nm) domain walls that interact more strongly with the electron spin, and higher magnetic resonance frequencies.  I’ll describe recent experimental and theoretical studies of the influence of spin currents on the field and angular dependence of the free layer switching fields, scaling of critical currents with energy barrier heights and the efficiency of spin currents on domain wall depinning.

[1]. J. A. Katine and E. E. Fullerton, J. Magn. Magn. Mater. 320, 1217 (2008).
[2] S. Mangin et al., Nature Mater. 5, 210 (2006).
[3] C. Burrowes et al., Nature Physics 6, 17 (2009).

Biography
Professor Fullerton received his B.Sc. in Physics from Harvey Mudd College in 1984 and his Ph.D. in physics from University of California, San Diego in 1991 where he worked on the growth and characterization of metallic superlattices.  He joined the magnetic films group in the Materials Science Division at Argonne National Laboratory as a postdoctoral fellow and in 1993 became a staff scientist specializing in the physics of coupled magnetic films.  In 1997 he joined the IBM Almaden Research Center where he worked until 2003 when he moved to Hitachi Global Storage Technologies as a Research Staff Member and Manager of the Fundamentals of Nanostructured Materials Group.  In 2006 he joined the University of California, San Diego as a Professor of Electrical and Computer Engineering and NanoEngineering and holder of an Endowed Chair in the Center of Magnetic Recording Research.