Immunity of nanoscale magnetic tunnel junctions to ionizing radiation

TL;DR

This study demonstrates that nanoscale magnetic tunnel junctions used in STT-MRAM are highly resistant to ionizing radiation, maintaining their key magnetic and electrical properties after gamma and neutron exposure, supporting their use in space and nuclear tech.

Contribution

The paper provides the first comprehensive experimental analysis of the radiation hardness of nanoscale MTJs in high-dose gamma and neutron environments, confirming their robustness for radiation-hard memory applications.

Findings

MTJs maintain tunneling magnetoresistance after irradiation

Magnetic field and current-induced switching are unaffected by radiation

Nanoscale MTJs are suitable for radiation-hard computing environments

Abstract

Spin transfer torque magnetic random access memory (STT-MRAM) is a promising candidate for next generation memory as it is non-volatile, fast, and has unlimited endurance. Another important aspect of STT-MRAM is that its core component, the nanoscale magnetic tunneling junction (MTJ), is thought to be radiation hard, making it attractive for space and nuclear technology applications. However, studies of the effects of high doses of ionizing radiation on STT-MRAM writing process are lacking. Here we report measurements of the impact of high doses of gamma and neutron radiation on nanoscale MTJs with perpendicular magnetic anistropy used in STT-MRAM. We characterize the tunneling magnetoresistance, the magnetic field switching, and the current-induced switching before and after irradiation. Our results demonstrate that all these key properties of nanoscale MTJs relevant to STT-MRAM applications are robust against ionizing radiation. Additionally, we perform experiments on thermally driven stochastic switching in the gamma ray environment. These results indicate that nanoscale MTJs are promising building blocks for radiation-hard non-von Neumann computing.