ABSTRACT
Spin currents have an important role in many proposed spintronic devices, as they govern the switching process of magnetic bits in random access memories or drive domain wall motion in magnetic shift registers. The generation of these spin currents has to be fast and energy efficient for realization of these envisioned devices. Recently it has been shown that femtosecond pulsed-laser excitation of thin magnetic films creates intense and ultrafast spin currents. Here we utilize this method to change the orientation of the magnetization in a magnetic bilayer by spin-transfer torque on sub-picosecond timescales. By analysing the dynamics of the magnetic bilayer after laser excitation, the rich physics governing ultrafast spin-transfer torque are elucidated opening up new pathways to ultrafast magnetization reversal, but also providing a new method to quantify optically induced spin currents generated on femtosecond timescales.
ABSTRACT
In this paper we present a multiple element magnetic device to guide atoms using a spatially inhomogeneous magnetic field formed by a series of permanent hexapole magnets. The operation of the device is demonstrated using an enhanced beam of neon atoms in the 3P2 metastable state. These atoms are guided around a bend of 30 degrees from their original path. A flux of 4.35 x 10(9) +/- 2 x 10(7) atoms s(-1) was measured after the device yielding a transmission efficiency of approximately 9% of the input flux. Simulations of the center of mass motion of the atoms through the magnetic guide have been performed giving reasonable agreement with the experimental results.
