Pulsed-current-induced domain wall propagation in permalloy patterns observed using magnetic force microscope

Pulsed-current controlled wall motion in 20 mum wide x 200 mum long x 160 nm thick patterned Permalloy strips was studied using magnetic force microscopy, By sequential imaging, the displacement of Bloch walls as far as 200 mum along the strip was observed, The direction of motion was in the same direction as the carrier velocity, which reversed with current polarity. The displacement per pulse was dependent upon the sample thickness and current density, which suggests that the mechanism is a combination of s-d exchange and hydromagnetic domain drag forces.