Throughout the human history there have been numerous memory devices. Now we are used to electronic means of preserving data, but not so long ago mechanical means were prominent. Simple note on a piece of paper could be considered a memory device also as it holds certain information.
Now scientists at the RIKEN Center for Emergent Matter Science think it is time to go back in time – they are considering replacing memory devices based on electrical manipulation on more mechanical gadgets.
If you are already thinking about steam-punk style devices and mechanical computers you will be disappointed. Instead, scientists are considering using a new way to manipulate skyrmions—tiny nanometre-sized magnetic vortices found at the surface of magnetic materials. This new method is what relies on using mechanical energy. There were speculations even before that skyrmions could be used in memory devices, because they are small and relative stability.
However, some research showed that such devices would not be competitive with current alternatives, as skyrmions are difficult to create, delete, and move. Study began with scientists wondering if these vortices could be manipulated by mechanical forces and what kind of force would be required. Researchers immediately thought it would require a substantial mechanical force.
With these assumptions research team set out to design a special stress probe that could apply mechanical stress to the surface of manganese-silicide, a “chiral magnetic” that is known to host skyrmions, cooled to very low temperature.
Surprisingly, scientists discovered that the force needed to create and destroy skyrmions was quite low, unlike their previous guesses. It only required less than ten nanonewtons per skyrmion. Such minute force is comparable to the pressure exerted by the tip of a simple conventional pencil when we write on a piece of paper.
Scientists also found that the direction of the applied force is critical to the manipulation of skyrmions. If mechanical force is being applied perpendicular to the magnetic field the skyrmions are created, while parallel force to the field turns them off. This means that it is possible to turn skyrmions on and off mechanically without the need of substantial mechanical power.
Yoshihiro Iwasa, leader of the Emergent Device Research Team, said: “This means that we may be able to fabricate devices in which skyrmions are created and deleted by a small mechanical force. This could be an inexpensive and low-energy-consuming way to create new low-cost memory devices and open the road to skymionics.”
However, not everything works perfectly now. The biggest drawback of the system is the required temperature. The surface of manganese-silicide has to be cooled to very low temperature for the system to work. Therefore, next steps of the research will be aimed at finding different materials that would still allow manipulating skyrmions mechanically, but at much higher temperatures.
We have been using similar memory devices for quite some time now. Although they are rapidly improving, they still suffer from short lifespan and reliability issues. Information now can be stored in clouds, but it is still not entirely perfect solution for every application and case. This is why such innovative ideas are relevant for current times, but we will have to wait and see if it will develop into a reliable and practical solution to current data storing problems.