Current Induced Switching of the Hard Layer in Perpendicular Magnetic Nanopillars

We report the spin-torque switching of the magnetization of the reference layer in a perpendicular magnetic anisotropy nanopillar with a spin-valve structure made of a combination of [Co/Pd] and [Co/Ni] multilayers. Around critical current, the switching is random, but becomes deterministic for larger currents. The threshold current is different for the two current directions, which shows that heating is not the main driving force but the spin torque interactions. A possible memory application is to store the magnetic bit in the magnetization of the hard magnetic reference layer and use the soft free layer to read and write it.