Magnetization Switching in Pentalayer Nanopillar with Oscillatory Interlayer Exchange Coupling

We investigated the influence of oscillatory interlayer exchange coupling (OXC) on spin transfer torque (STT)-assisted magnetization switching in the pentalayer nanopillar structure. The impact of OXC between the ferromagnetic layers in the pentalayer nanopillar is realised by solving the associated governing equation, namely Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. First, we calculated the critical current density needed to switch the magnetization of the free layer in the absence of OXC by analytically solving the LLGS equation and its value is J(c) = 0.46 x 10(11)Am(-2). Then, we studied the influence of thickness of the spacer layer on the OXC field term and how it affects the critical current density and magnetization switching behaviour by numerical simulations of LLGS equation. By controlling OXC, we reduce critical current density and magnetization switching time from peak values to 86% and 82%, respectively, which is accomplished by constructing a multilayer with optimal spacer layer thickness of 1.7 to 1.9 nm. This work paves a potential way for practical implementation of STT-based MRAMs, nano-oscillators, and logic devices.