Energy-efficient ultrafast SOT-MRAMs based on low-resistivity spin Hall metal Au0.25Pt0.75

TL;DR

This paper demonstrates that low-resistivity Au0.25Pt0.75 thin films enable ultrafast, energy-efficient SOT-MRAMs with switching times as short as 200 ps, promising for high-performance memory applications.

Contribution

It introduces the use of Au0.25Pt0.75 spin Hall metal for ultrafast SOT-MRAM switching, achieving significant improvements in speed and energy efficiency over prior materials.

Findings

Achieved 200 ps switching with <1 fJ energy per write.

Demonstrated 10x faster switching than macrospin model predictions.

Showed reliable switching with low error rates at nanosecond pulses.

Abstract

Many key electronic technologies (e.g., large-scale computing, machine learning, and superconducting electronics) require new memories that are fast, reliable, energy-efficient, and of low-impedance at the same time, which has remained a challenge. Non-volatile 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. This work reports that the spin Hall effect of low-resistivity Au0.25Pt0.75 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, our results show that an optimized MRAM cell based on Au0.25Pt0.75 can have energy-efficient, ultrafast, and reliable switching, e.g. a write energy of < 1 fJ (< 50 fJ) for write error rate of 50% (<1e-5) for 1 ns pulses. The antidamping torque switching of the Au0.25Pt0.75 devices is 10 times faster than expected from a rigid macrospin model, most likely because of the fast micromagnetics due to the enhanced non-uniformity within the free layer. These results demonstrate the feasibility of Au0.25Pt0.75-based SOT-MRAMs as a candidate for ultrafast, reliable, energy-efficient, low-impedance, and unlimited-endurance memory.