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A University of Tokyo-led research team has demonstrated a non-volatile spintronic memory switching device that can rewrite a magnetic state in 40 ps, using an antiferromagnetic manganese-tin structure rather than stored electrical charge.

The work, announced by the University of Tokyo School of Science and published in Science, is aimed at one of the central limits in AI servers and high-speed computing: switching and moving data without converting most of the input energy into heat.

Spintronic memory uses magnetic state switching

The device uses the antiferromagnetic material Mn₃Sn with tantalum. Instead of storing data as capacitor charge, as in DRAM, it uses magnetic states to represent binary values. Short electrical pulses generate spin-orbit torque, transferring angular momentum into the magnetic structure and changing its state.

The researchers report switching with 40 ps electrical pulses. They also demonstrated switching using 60 ps photocurrent pulses produced by combining a telecom-wavelength laser with a photoelectric converter. That second result is important because it links optical signalling to direct writing of a non-volatile state.

For context, a 5 GHz processor cycle lasts 200 ps. A memory-switching process that takes 1 ns spans several such cycles, while a 40 ps event fits well inside one. That does not make the device a commercial memory chip, but it shows why picosecond switching is attractive for future processor and data-centre architectures.

Spintronic memory still has practical hurdles

The claim is not that DRAM has been replaced. This is still a laboratory switching device, not an addressable memory array ready for manufacturing. Density, retention, endurance in real systems, CMOS integration, bias-field requirements and cost all remain open engineering questions.

Even so, the result adds weight to the case for magnetic and antiferromagnetic approaches to future memory. As we reported previously when researchers in Japan developed low power spintronic ME-MRAM memory, magnetic memories are being pursued as a way to reduce standby power and avoid the continual refresh overhead of charge-based memory.

The latest spintronic memory demonstration pushes that discussion into the picosecond regime. Its near-term value is as a materials and device result, particularly for optical-to-electrical conversion and low-heat switching, rather than as a near-term drop-in replacement for DRAM, SRAM or NAND.

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