Spin transfer switching characteristics in a [Pd/Co]m/Cu/[Co/Pd]n pseudo spin-valve nanopillar with perpendicular anisotropy

Abstract

We successfully demonstrate spin transfer switching (STS) characteristics in a [Pd/Co]m/Cu/[Co/Pd]n pseudo spin-valve nanopillar with 100 nm diameter. We observed lower critical current density and high giant magnetoresistance (GMR) ratio in our devices compared to other fully perpendicularly magnetized pseudo spin-valve structures. The devices showed a current-perpendicular-to-plane GMR of 1.2% and a STS critical current density of JAP-P = −2.6 × 107 A/cm2 and JP-AP = 3.8 × 107 A/cm2. The observed low critical current density is thought to be due to higher spin-transfer efficiency arising from smaller spin orbital scattering, longer spin diffusion length of the thinner Pd, and thinner soft-layer-film thickness and coercivity in the nanopillar devices.