Sub-Nanosecond Precessional Switching in a MRAM Cell with a Perpendicular Polarizer

This work reports sub-nanosecond precessional spin-transfer switching in elliptical magnetic tunnel junction nanopillars. This result is obtained in samples integrating a perpendicular polarizer and a tunnel junction with in-plane magnetized electrodes. We have performed statistics on time-resolved electrical measurements showing oscillations of the switching probability as a function of write voltage pulse width. This behavior is characteristic of the free layer precessional motion induced by the perpendicular polarizer. Ultrafast STT switching in less than 300ps could be achieved in these structures with corresponding write energy less than 100fJ.