  Microwave assisted magnetization reversal has been investigated in a bilayer
system of Pt/ferromagnet by detecting a change in the polarity of the spin
pumping signal. The reversal process is studied in two material systems,
Pt/CoFeB and Pt/NiFe, for different aspect ratios. The onset of the switching
behavior is indicated by a sharp transition in the spin pumping voltage. At a
threshold value of the external field, the switching process changes from
partial to full reversal with increasing microwave power. The proposed method
provides a simple way to detect microwave assisted magnetization reversal.
