Magnetic memory driven by topological insulators

It remains challenging to integrate topological insulators (TI) with magnetic tunnel junctions (MTJ) for spintronics applications. Here, the authors achieve a large tunneling magnetoresistance ratio and a low switching current density in a TI-MTJ device at room temperature, very promising for TI-driven magnetic memory. Giant spin-orbit torque (SOT) from topological insulators (TIs) provides an energy efficient writing method for magnetic memory, which, however, is still premature for practical applications due to the challenge of the integration with magnetic tunnel junctions (MTJs). Here, we demonstrate a functional TI-MTJ device that could become the core element of the future energy-efficient spintronic devices, such as SOT-based magnetic random-access memory (SOT-MRAM). The state-of-the-art tunneling magnetoresistance (TMR) ratio of 102% and the ultralow switching current density of 1.2 x 10(5) A cm(-2) have been simultaneously achieved in the TI-MTJ device at room temperature, laying down the foundation for TI-driven SOT-MRAM. The charge-spin conversion efficiency theta(SH) in TIs is quantified by both the SOT-induced shift of the magnetic switching field (theta(SH) = 1.59) and the SOT-induced ferromagnetic resonance (ST-FMR) (theta(SH) = 1.02), which is one order of magnitude larger than that in conventional heavy metals. These results inspire a revolution of SOT-MRAM from classical to quantum materials, with great potential to further reduce the energy consumption.

Automated summary

This study demonstrates a TI-MTJ device with a high tunneling magnetoresistance ratio and low switching current density at room temperature, showing great potential for TI-driven magnetic memory. The results suggest a potential revolution of SOT-MRAM from classical to quantum materials, with the ability to further reduce energy consumption.