Switching in spin-valve devices in response to subnanosecond longitudinal field pulses

We have fabricated spin-valve devices in a high-speed test structure that allows subnanosecond pulsed field excitation and high-bandwidth observation of the magnetoresistance response. The switching response varies for low-amplitude field pulses and approaches a consistent fast switch of less than 1 ns for field pulses of higher amplitude. For several pulse widths and amplitudes, the device switches into metastable states. The threshold amplitude of the write-pulse was measured as a function of pulse duration for pulses as small as 250 ps in duration. [S0021-8979(00)55408-5].