Spin torques estimation and magnetization dynamics in dual barrier resonant tunneling penta-layer magnetic tunnel junctions

Abstract

We investigate electronic transport and magnetization dynamics associated with current induced spin-torque effects in dual barrier magnetic tunnel junctions using Non-Equilibrium Green's Function formalism and Landau-Lifshitz- Gilbert (LLG) equation self-consistently. In a dual barrier penta-layer MTJ, a set of geometry and band-structure parameters including the free-layer thickness, oxide barrier height, width of the tunneling barrier and applied voltage jointly determines the position of resonant peaks and valleys within the energy range of interest. The combined effect of these design parameters to enhance the in-plane and out-of-plane spin-torque efficiencies in both aligned and anti-aligned penta-layer MTJs [Fig. 1] has been studied comprehensively. We quantify the impact of non-monotonic quantum well states for majority and minority spin electrons inside the thin free layer on the spin-torque effects in penta-layer MTJs. We essentially explore the design space for both the aligned and anti-aligned penta-layer MTJs optimized for read/write stabilities, improved TMR and low power. The crucial role of anti-aligned penta-layer MTJs in reducing the Energy-Delay-Product (EDP) during write over tri-layer MTJs has also been reported quantitatively.