Two-terminal spin–orbit torque magnetoresistive random access memory

Abstract

Spin-transfer torque magnetoresistive random access memory (STT-MRAM) is an attractive alternative to existing random access memory technologies due to its non-volatility, fast operation and high endurance. However, STT-MRAM does have limitations, including the stochastic nature of the STT-switching and a high critical switching current, which makes it unsuitable for ultrafast operation in the nanosecond and subnanosecond regimes. Spin–orbit torque (SOT) switching, which relies on the torque generated by an in-plane current, has the potential to overcome these limitations. However, SOT-MRAM cells studied so far use a three-terminal structure to apply the in-plane current, which increases the size of the cells. Here we report a two-terminal SOT-MRAM cell based on a CoFeB/MgO magnetic tunnel junction pillar on an ultrathin and narrow Ta underlayer. In this device, in-plane and out-of-plane currents are simultaneously generated on application of a voltage, and we demonstrate that the switching mechanism is dominated by SOT. Spin–orbit torque switching in a two-terminal magnetoresistive random access memory cell can reduce critical write current by more than 70% compared with an equivalent spin-transfer torque device.

Cite this article

Sato, N., Xue, F., White, R.M. et al. Two-terminal spin–orbit torque magnetoresistive random access memory. Nat Electron 1, 508–511 (2018). https://doi.org/10.1038/s41928-018-0131-z

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