Sub-nanosecond spin-torque switching of perpendicular magnetic tunnel junction nanopillars at cryogenic temperatures

Abstract

Spin-transfer magnetic random access memory devices are of significant interest for cryogenic computing systems where a persistent, fast, low-energy consuming, and nanometer scale device operating at low temperature is needed. Here, we report the low-temperature nanosecond duration spin-transfer switching characteristics of perpendicular magnetic tunnel junction (pMTJ) nanopillar devices (40-60 nm in diameter) and contrast them to their room temperature properties. Interestingly, the characteristic switching time decreases with temperature, with the largest reduction occurring between room temperature and 150 K. The switching energy increases with decreasing temperature, but still compares very favorably with other types of spin-transfer devices at 4 K, with <300 fJ required per switch. Write error rate (WER) measurements show highly reliable switching with WER ≤ 5 × 10-5 with 4 ns pulses at 4 K. Our results demonstrate the promise of pMTJ devices for cryogenic applications and show routes to further device optimization.