Figure 1
Credit: Alan Stonebraker

Figure 1: Permalloy disk sample and contacts for current injection. (Top) Four 90° domain walls intersect at the vortex core with its out-of-plane magnetization. (Bottom) As current flows through the disk, the vortex core is displaced due to the magnetic field of the current and due to spin-transfer torque. This displacement has been measured to quantify the nonadiabatic part of spin torque.