You may not know it, but chances are you use spintronics every day. Spintronics is the technology that uses the magnetic spin states of electrons to store and process data. It appears in the magnetic processes that store data in multi-terabyte desktop hard drives; and in the magnetoresistive random-access memory (MRAM) at the heart of microprocessors that likely run your car’s electronics and its black box event recorder.

Currently, MRAMs use electric and magnetic methods to reach nanosecond read and write speeds, like conventional RAMs. And they have additional advantages: The MRAM retains its data while its power is off; it does not need to be refreshed, which reduces overall power usage; and it resists radiation damage better. These are important bonuses for critical and demanding applications like computing in massive data centers.

Even better, MRAM devices could potentially break the nanosecond speed barrier. Fast laser pulses can initiate magnetic states in picoseconds, but these also decay in nanoseconds at most, which is too quick to currently be useful. But now an international research team has used laser light differently to induce magnetism in picoseconds, and in a first, initiated a magnetic state that lasted for milliseconds. This opens the door to finding a useful combination of rapid turn-on and stable response for spintronic RAMs.

Shining a Light on Faster Spintronics

The observation that light and a magnetic field can affect each other goes back to the 19th century. In 1845, Michael Faraday founded opto-magnetics when he discovered the Faraday effect: the plane of polarization of light changes when passing through a magnetic field. Since the 2000s, researchers have found that high-power laser pulses of visible or infrared light rapidly change the magnetic state of certain magnetic materials in picoseconds. But there were complications such as the fact that