Nanosecond switching in thin magnetic films (Reprinted from IBM Journal ofResearch and Development, vol 4, 1960)

A special pulse equipment including a pulse-sampling oscilloscope with an o ver-all response time of 0.35 nanosecond (10(-9) sec) for the observation o f the nanosecond flux change in thin permalloy films is described. Film swi tching signals as short as 1 nanosecond have been obtained and are discusse d with respect to the underlying processes. Inverse switching time versus d riving-field curves have been plotted for films of different thicknesses. T hey snow mar thinner films switch faster than thicker ones. The slopes or t hese curves have characteristic values in the nanosecond region of about 10 (8) per oersted-second. Coherent rotation and oscillation of the magnetizat ion have been clearly detected by picking up the flux change transverse to the driving field.