2X reduction of STT-MRAM switching current using double spin-torque magnetic tunnel junction

Abstract

We introduce a new device for reducing the switching current, Ic, in Spin-Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM). The Double Spin-torque Magnetic Tunnel Junction (DS-MTJ) uses spin torque from both top and bottom free-layer interfaces to reduce Ic by 2x. However, unlike previous work using Double Magnetic Tunnel Junctions (DMTJs), the DS-MTJ does not suffer from reduced magnetoresistance (MR) due to increased series resistance. Experimental data using 10 ns write pulses demonstrates 2x reduction in Ic, and reliable writing down to an error-floor of write-error-rate (WER) = 1e-6.