Generation of nanosecond magnetic pulse field for switching experiments on a single Co/Pt nanodot

A one-turn Cu microcoil being able to generate a large perpendicular pulse field was fabricated on a Co/Pt multilayer dot of 300 nm in diameter covered with electrodes for anomalous Hall effect measurement. Rectangular electric pulses with the maximum amplitude of 160 V and the duration τp =1.8-20.8 ns were transmitted through the coil without any significant distortion. The magnetization of the dot was successfully switched solely by the pulse field with the maximum value of 2.7 kOe. No significant dependence of the nucleation field for a reversed embryo in the dot was found over the range of τp examined in the present study. Based on the Ńel-Arrhenius model, the activation energy for nucleation of the reversed embryo was evaluated to be 6× 10-12 erg.