Size dependance effects in sub-ns magnetization switching using spin-transfer torque

This paper investigates the switching speed in samples having different surfaces (hereafter quoted as "small" or "large" samples), and compares the temperature dependences thereof. The "large" samples are pseudo-spin valves Co75Fe25 (2.5 nm)/Cu(6 nm)/Co75Fe25(40 nm). The top (thin) layer is patterned into an ellipse of size 150times85 nm, while the bottom layer is unpatterned. The "small" samples are PtMn17.5/CoFel.8/Ru8/CoFe2/Cu3.5/CoFel/NiFel.8 nm films, etched into pillar hexagons of 75times113 nm. The switching speeds have been compared from 40K to 300K, for pulse durations from 0.1 to 10 ns.