부산대학교 도서관

The Double Magnetic Tunnel Junction (D-MTJ) is a promising approach to lower the required switching current of Spin Transfer Torque Magnetic Random Access Memory (STT-MRAM). However, one of the primary challenges is that two MgO barriers are required, reducing the Tunnel Magnetoresistance Ratio (TMR) due to both a competing magneto resistance and increase Resistance Area product (RA). In this work, a spacer-less Free-Layer (FL) is proposed to remove the competing TMR, while maintaining the switching current benefit. Device performance demonstrates this with J sw = 2.3 MA/cm 2 at 50 ns, for a retention of Δ = 50k B T while maintaining a TMR = 120%. However, the Spin Torque Efficiency (STE) is still less than that promised in the literature. Micromagnetic simulations are used to show that this is likely due to a competition of a gradient in A ex , M s and an anti-symmetric coupling strength across the MgO barriers.