Effective bit addressing times for precessional magnetization reversal in a magnetic memory cell

The effective bit addressing times for precessional magnetization reversal in magnetic random access memory cells is studied. Different addressing times /spl tau//sub S/ for switching and /spl tau//sub NS/ for non-switching are studied using a magneto transport setup. The ultra fast magnetisation dynamics of the free layer is accessed by reading out the tunnelling magneto resistance (TMR) response of the cell using a fast sampling oscilloscope. From the measured TMR, the time evolution of the easy axis magnetization component m/sub x/ of the free layer is derived. Bit addressed switching of the free layer is studied by application of a fast perpendicular field pulse in combination with an easy axis bias field.