Experimental and Simulation Study to Identify Current-Confined-Path in Cu-Al Space Layer for CPP-GMR Spin-Valve Applications

Joon-Young Soh, Sang-Pil Kim, Young Keun Kim, Kwang-Ryeol Lee, Yong-Chae Chung, S. Kawasaki, K. Miyake, M. Doi, M. Sahashi
 

To understand the mechanism of the currentconfined-path formation for the current-perpendicular-to-plane type of giant magnetoresistive devices, we attempted to understand the evolution of an Al monolayer on the Cu (111) surface both by in situ scanning tunneling microscopy and by molecular dynamics simulation. Ultrathin Al nano-clusters were formed on the plateaus and step (or plateau) edges of the Cu surface in the as-deposited state. Upon annealing at 300ºC, Al atoms migrated toward the step edges by surface diffusion. As a consequence, nanometer-sized Cu channels not covered by Al clusters can be formed. These channels could serve as currentconfined-paths if subsequent mild Al oxidation is provided.