Spin Transfer Torque driven dynamics of the synthetic antiferromagnetic reference layer of perpendicular MRAM devices

Spin Transfer Torque Magnetic Random Access Memories (STT-MRAM) are based on Magnetic Tunnel Junctions (MTJs) made out of two ferromagnetic electrodes separated by a MgO tunnel barrier. Here we report experimental data of the STT-induced dynamics of a SAF RL in perpendicularly magnetized STT-MRAM devices. We show evidence of different RL dynamical modes depending on the SAF properties. We also develop an analytical model based on a 3-layer macrospin model, which allows us to reproduce the main feature of the experimental data and to derive a phase diagram of the RL dynamics. Experimental data of RL dynamics are obtained using time-resolved resistance measurements of individual MRAM devices.