A perpendicular spin transfer torque memory (pSTTM) device incorporates a magnetic tunnel junction (MTJ) device having a free magnetic stack that includes a plurality of magnetic layers interleaved with a plurality of non-magnetic insert layers. The layers are arranged such that the topmost and bottommost layers are magnetic layers. The stacked design decreases the damping of the MTJ free magnetic stack, beneficially reducing the write current required to write to the pSTTM device. The stacked design further increases the interface anisotropy, thereby beneficially improving the stability of the pSTTM device. The non-magnetic interface layer may include tantalum, molybdenum, tungsten, hafnium, or iridium, or a binary alloy containing at least two of tantalum, molybdenum, tungsten hafnium, or iridium.