Resonant Spin-Transfer-Driven Switching of Magnetic Devices Assisted by Microwave Current Pulses

TL;DR

This paper demonstrates that microwave-frequency pulses can resonantly excite nanomagnets, improving switching efficiency and reducing power consumption in spin-transfer-driven magnetic devices, advancing MRAM technology.

Contribution

It introduces the use of microwave-frequency pulses to enhance spin-torque switching, showing improved switching time and power efficiency over traditional square pulses.

Findings

Microwave pulses induce resonant excitation of nanomagnets.

Switching time is reduced with microwave assistance.

Power consumption for switching is significantly lowered.

Abstract

The torque generated by the transfer of spin angular momentum from a spin-polarized current to a nanoscale ferromagnet can switch the orientation of the nanomagnet much more efficiently than a current-generated magnetic field, and is therefore in development for use in next-generation magnetic random access memory (MRAM). Up to now, only DC currents and square-wave current pulses have been investigated in spin-torque switching experiments. Here we present measurements showing that spin transfer from a microwave-frequency pulse can produce a resonant excitation of a nanomagnet and lead to improved switching characteristics in combination with a square current pulse. With the assistance of a microwave-frequency pulse, the switching time is reduced and achieves a narrower distribution than when driven by a square current pulse alone, and this can permit significant reductions in the integrated power required for switching. Resonantly excited switching may also enable alternative, more compact MRAM circuit architectures.