Swiss researchers close to single-atom magnetic data storage

Source: Xinhua| 2018-07-14 05:06:36|Editor: Mu Xuequan
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GENEVA, July 13 (Xinhua) -- Swiss researchers have successfully tested the stability of a magnet made up of a single atom, which is a step close to single-atom storage devices that promise enormous data capacities with each atom able to store a single bit of data, according to the Swiss Federal Institute of Technology Lausanne (EPFL) on Friday.

Despite the rise of solid-state drives, magnetic storage devices such as conventional hard drives and magnetic tapes are still very common. But as our data-storage needs are increasing at a rate of almost 15 million gigabytes per day, scientists are turning to alternative storage devices.

One of these are single-atom magnets, which are storage devices consisting of individual atoms stuck on a surface, each atom able to store a single bit of data that can be written and read using quantum mechanics. And because atoms are tiny enough to be packed together densely, single-atom storage devices promise enormous data capacities.

In a new study published in Physical Review Letters, physicists at EPFL have demonstrated the stability of a magnet consisting of a single atom of holmium, an element they have been working with for years.

Thy exposed the atom to extreme conditions that normally de-magnetize single-atom magnets, such as temperature and high magnetic fields, all of which would pose risks to future storage devices.

Using a scanning tunneling microscope, which can "see" atoms on surfaces, the scientists found that the holmium atoms could retain their magnetization in a magnetic field exceeding eight Tesla, which is around the strength of magnets used in the Large Hadron Collider at CERN. The authors describe this as the ability of a magnet to withstand an external magnetic field without becoming demagnetized.

Then they turned up the heat and exposed a series of Holmium single-atom magnets to temperatures of up to 45 Kelvin, or -233.15 degrees Celsius, which, for single atoms, is like being in a sauna. The Holmium single-atom magnets remained stable up to a temperature of 35K, and only at around 45K, the magnets began to spontaneously align themselves to the applied magnetic field.

This showed that they can withstand relatively high temperature perturbations and might point to the way forward for running single-atom magnets at more commercially viable temperatures.

However, researchers say single-atom magnets are still in basic research, with many fundamental obstacles to be overcome before they can be implemented into commercial devices.

Next they will need to learn how to write information to those bits more effectively to overcome the stability, writability, and signal-to-noise ratio of magnetic recording.