A hard drive breakthrough could reduce a major source of carbon emissions

A new breakthrough in data storage could enable computer servers to store larger amounts of data, retrieve information faster, and use less energy. The idea, the researchers claim, could cut back carbon emissions for an industry that produces a similar amount as aviation.

Researchers at the University of Edinburgh developed a single-molecule magnet whose magnetic properties can be altered by shining a laser light. This could be used to power a futuristic hard drive, where the magnets store data and laser pulses are used to retrieve it when needed. Using pulses that last one millionth of a billionth of a second, these hard drives could process information up to 100 times faster than present-day drives.

The paper, titled "Vibrational coherences in manganese single-molecule magnets after ultrafast photoexcitation," was published in the journal Nature Chemistry Monday.

Although focused on cloud-based servers, the idea could offer big benefits for broader society. Services like Apple iCloud, Dropbox and Google Drive have blurred the line between a user's locally-stored files and those hosted on servers accessible over the internet. The global number of personal cloud storage users is expected to hit 2.3 billion this year, up from 1.1 billion in 2014.

These services, while popular, consume a lot of energy. The Guardian affiliate Climate Home News reported in 2017 that the communications industry could use 20 percent of global electricity by 2025. While a more recent study published in Science in February 2020 found they consume less than previously feared, thanks to advancements in energy efficiency, that doesn't mean they're exactly green. Data centers are estimated to account for one percent of electricity usage. Continuing research in this area could help these expanding services keep energy use down.

"There is an ever-increasing need to develop new ways of improving data storage devices," Olof Johansson, lead researcher from the university's school of chemistry, said in a statement. "Our findings could increase the capacity and energy efficiency of hard drives used in cloud-based storage servers, which require tremendous amounts of power to operate and keep cool. This work could help scientists develop the next generation of data storage devices."

The idea would improve on the current design of the hard drive. The spinning disks have been gradually replaced by speedier solid-state storage in many consumer products, but they remain in use in some areas thanks to their low price per gigabyte. Hard drives work by passing an electrical current through a wire, which generates a magnetic field.

The team's proposed alternative would use a laser-activated system to manage the data. This would mean the system won't produce as much heat, which should mean it uses energy more efficiently.

If the idea reaches the market, it could help cloud servers avoid throwing out more clouds of fumes.

Abstract: Magnetic recording using femtosecond laser pulses has recently been achieved in some dielectric media, showing potential for ultrafast data storage applications. Single-molecule magnets (SMMs) are metal complexes with two degenerate magnetic ground states and are promising for increasing storage density, but remain unexplored using ultrafast techniques. Here we have explored the dynamics occurring after photoexcitation of a trinuclear µ₃-oxo-bridged Mn(III)-based SMM, whose magnetic anisotropy is closely related to the Jahn–Teller distortion. Ultrafast transient absorption spectroscopy in solution reveals oscillations superimposed on the decay traces due to a vibrational wavepacket. Based on complementary measurements and calculations on the monomer Mn(acac)₃, we conclude that the wavepacket motion in the trinuclear SMM is constrained along the Jahn–Teller axis due to the µ₃-oxo and µ-oxime bridges. Our results provide new possibilities for optical control of the magnetization in SMMs on femtosecond timescales and open up new molecular-design challenges to control the wavepacket motion in the excited state of polynuclear transition-metal complexes.