| AVS 56th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Thursday Sessions |
| Session MI+TF-ThA |
| Session: | Magnetic Thin Films: Multilayers and Nanostructures |
| Presenter: | E.E. Fullerton, University of California, San Diego |
| Authors: | E.E. Fullerton, University of California, San Diego I. Tudosa, University of California, San Diego J. Cucchiara, U. Nancy, France S. Mangin, U. Nancy, France Y. Henry, IPCMS, France J. Katine, Hitachi GST D. Ravelosona, IEF, France |
| Correspondent: | Click to Email |
Spin torque reversal of nano-elements with perpendicular magnetic anisotropy have considerable interest for both the fundamental study of spin torque reversal and for possible spin-torque based devices. This ability to locally control magnetization opens the door to a range of applications such as high-density magnetic random access memories, tunable high frequency oscillators and possibly programmable logic devices. In perpendicular anisotropy systems the demagnetization field is commensurate with the anisotropy axis and can be described as an effective uniaxial anisotropy. Both the critical current for spin-torque reversal and the thermal stability are then proportional to the effective anisotropy [1-3] as shown experimentally for [Co/Pt]/[Co/Ni]/Cu/[Co/Ni] nano-pillar samples[2, 3]. In this presentation we describe recent experimental and theoretical studies of the influence of spin currents on the field and angular dependence of the free layer switching fields. The angular dependence of the switching field in the absence of current is well described by the Stoner-Wohlfarth asteroid for a uniaxial system. With the addition of current we find that spin-torque reversal is most efficient when the applied field is parallel to the anisotropy axis. Surprisingly, for fields applied at an angle to the anisotropy axis the switching fields are current independent for currents lower than a critical value and the critical current increases with increasing field angle. We will discuss the origin of this phenomena and results for coupled reversal of the free and reference layer.
[1]. J. A. Katine and E. E. Fullerton, J. Magn. Magn. Mater. 320, 1217 (2008).
[2] S. Mangin et al., Nat. Mater. 5, 210 (2006).
[3] S. Mangin et al., Appl. Phys. Lett. 94, 012502 (2009).