STT-MRAM with double magnetic tunnel junctions

We report switching performance of perpendicularly magnetized Spin-Transfer Torque MRAM (STT-MRAM) devices with double tunnel barriers and two reference layers. We show that stacks with double tunnel barriers improve the switching efficiency (Eb/Ic0) by 2x, when compared to similar stacks with a single tunnel barrier. Switching efficiency up to 10 kBT/uA was observed in single devices. A large operating window, Vbreakdown-Vc10ns ∼ 0.7 V was achieved for 40nm devices, compared to 0.2V in single tunnel barrier devices.