Magnetic Properties of Perpendicularly Magnetized [Co/Pd]/Au/[Co/Pd] Pseudo-Spin-Valve Nano-Ring Structures

We systematically investigate the effects of interlayer, inter-ring dipolar coupling and the number of bilayer repeats on the magnetization reversal process of [Co/Pd]/Au(
t
)/[Co/Pd] pseudo-spin-valve (PSV) nano-rings. We observed that exchange coupling dominates the magnetization reversal process in PSV rings when the Au spacer layer thickness is 1 nm, while magnetostatic coupling plays a more significant role for thicker spacer layer. The magnetization reversal process of the PSV nano-rings as a function of inter-ring spacing provides a way to engineer the switching fields in both the ferromagnetic layers. We observed that the coercivity of both the top and bottom Co/Pd stack increases with increasing inter-ring spacing.