Precessional magnetization reversal in microscopic spin valve cells

Summary form only given. We have demonstrated precessional switching of the free layer magnetization of microscopic spin valve (SV) elements, under the application of ultra short hard axis magnetic field pulses. The magnetic devices consist of patterned 1/spl times/4 and 2/spl times/4 /spl mu/m/sup 2/ SV elements showing a magneto resistance (MR) change of up to 5%, with nearly perfectly square MR loops. This maybe due to the fact that closure domains at both ends do not contribute to the signal because of the overlap of the electrical contacts to the elements. These contacts as well as an integrated pulse line are designed as high bandwidth coplanar wave guides (40 GHz). They allow us to apply ultra fast magnetic field pulses (pulse width 0.1-10 ns, rise time /spl sim/50 ps, max. field /spl sim/200 Oe) and to measure the magneto resistance variation using a fast sampling oscilloscope.