Energy‐Efficient Ultrafast SOT‐MRAMs Based on Low‐Resistivity Spin Hall Metal Au<sub>0.25</sub>Pt<sub>0.75</sub>
Lijun Zhu, Lijun Zhu, Lujun Zhu, Lujun Zhu, Shengjie Shi, Daniel C. Ralph, R. A. Buhrman
Abstract
Abstract Many key electronic technologies (e.g., large‐scale computing, machine learning, and superconducting electronics) require new memories that are at the same time fast, reliable, energy‐efficient, and of low‐impedance, which has remained a challenge. Nonvolatile magnetoresistive random access memories (MRAMs) driven by spin–orbit torques (SOTs) have promise to be faster and more energy‐efficient than conventional semiconductor and spin‐transfer‐torque magnetic memories. It is reported that the spin Hall effect of low‐resistivity Au 0.25 Pt 0.75 thin films enables ultrafast antidamping‐torque switching of SOT‐MRAM devices for current pulse widths as short as 200 ps. If combined with industrial‐quality lithography and already‐demonstrated interfacial engineering, an optimized MRAM cell based on Au 0.25 Pt 0.75 can have energy‐efficient, ultrafast, and reliable switching, for example, a write energy of <1 fJ (<50 fJ) for write error rate of 50% (<10 −5 ) for 1 ns pulses. The antidamping torque switching of the Au 0.25 Pt 0.75 devices is ten times faster than expected from a rigid macrospin model, most likely because of the fast micromagnetics due to the enhanced nonuniformity within the free layer. The feasibility of Au 0.25 Pt 0.75 ‐based SOT‐MRAMs as a candidate for ultrafast, reliable, energy‐efficient, low‐impedance, and unlimited‐endurance memory is demonstrated.