The effect of pulse rise time on nanosecond switching in magnetic thin films

Nanosecond switching in thin magnetic films is studied by the application of easy-axis pulses with rise times from 0.4 ns to 50 ns. Switching time data with selected hard-axis bias fields and with the rise time as a parameter are presented. The switching mechanism depends on the percentage of flux switched during the ramp portion of the pulse. A comparison between the experimental data and numerical solutions based on the rotational model and the corresponding transverse signals shows that for pulses with amplitudes larger than the experimental astroid values (coherent rotation with 0.4 ns pulses) but with rates of increaseS < 10^{9}Oe/s, the stray field interaction between partially switched and unswitched regions causes appreciable flux to switch incoherently.