What is it about?

As an emerging technology in this post-Moore era, Magnetic Random-Access Memory (MRAM) offers substantial potentials to enable next-generation memory architecture. Inside the MRAM bits (termed as MTJs), data are “written” by switching the direction of the spins. Thus, MRAM allows data to be saved in an enduring manner when the power is off. Over the past 25 years, two major generations of MRAMs have been released to the market. However, the data writing process of all these MRAM bits have been hindered by a long-lasting challenge: the speed is fundamentally limited in the ns regime, with too much power consumption as well. In this work, researchers from the Fert Beijing Institute of Beihang University (PI: Prof. dr. Weisheng Zhao), and the Eindhoven University of Technology (PI: Prof. dr. Bert Koopmans) have targeted on such an intrisic bottleneck, by successfully integrating All-Optical Switching mechansim with a MRAM cell.

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Why is it important?

Inspired by a spintronic-photonic interdisciplinary mindset, the highlight of this device is the picosecond (10^-12) writing speed, i.e., 1 – 2 orders of magnitude faster than state-of-the-art MRAMs, with an enhanced energy efficiency (≈ 100 fJ to switch a 50×50 nm2 sized bit) as well.


As a first step towards the “opto-MRAM” chip, it would be highly promising towards a unique non-volatile photonic memory, by directly converting optical stimulus into magnetic information. Moreover, the experimental results may also represent an advance to fuel further fundamental scientific studies regarding the interaction between spintronics and photonics.

Luding Wang
Technische Universiteit Eindhoven

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This page is a summary of: Picosecond optospintronic tunnel junctions, Proceedings of the National Academy of Sciences, June 2022, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.2204732119.
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