Ultrafast magnetic field pulses as short as 2 picoseconds are able to reverse the magnetization in thin, in-plane, magnetized cobalt films. The field pulses are applied in the plane of the film, and their direction encompasses all angles with the magnetization. At a right angle to the magnetization, maximum torque is exerted on the spins. In this geometry, a precessional magnetization reversal can be triggered by fields as small as 184 kiloamperes per meter. Applications in future ultrafast magnetic recording schemes can be foreseen.
Back, C. H., Allenspach, R., Weber, W., Parkin, S. S. P., Weller, D., Garwin, E. L., & Siegmann, H. C. (1999). Minimum field strength in precessional magnetization reversal. Science, 285(5429), 864–867. https://doi.org/10.1126/science.285.5429.864