Can Information Be Stored on a Single Atom?
In the data storage arena, now that scientist can essentially see an atom's electronic and magnetic properties, they can study whether information can reliability be stored on a single atom. IBM scientists were able to develop a new technique for the STM that enabled it to record the behavior of atoms stroboscopically, similar to how the first movies were created or to time-lapse photography. This was needed because the magnetic spin of an atom changes too fast to measure directly using the STM, according to the company.For each time increment, the alternating pulses are repeated about 100,000 times, which takes less than a second. IBM scientists used iron atoms that were put onto an insulating layer one atom thick and supported on a copper crystal and position next to non-magnetic copper atoms. The structure was then measured when in the presence of different magnetic fields, which showed that the speed at which they changed their magnetic orientation depends on the magnetic field. Essentially, the scientists found that the atom's magnetism can reverse direction without having to go through intermediate orientations. Knowing this, researchers may be able to engineer the magnetic lifetime of the atoms to make them longer-to retain their magnetic state-or shorter-to switch to new magnetic states-as needed. "This breakthrough allows us-for the first time-to understand how long information can be stored in an individual atom, Sebastian Loth, at IBM Research, said in a statement. "Beyond this, the technique has great potential because it is applicable to many types of physics happening on the nanoscale." IBM Research's Heinrich said it is far too early to tell if or how this will result in productized technologies. It will probably take another two to five years to determine whether atoms can be manipulated to store data for hours or days, rather than nanoseconds, and even longer-15 years or more-to determine whether any of this research will result in products. Finding that out is the goal, he said. "Jumping to the scale of a single atom, that is clearly at the end of the road map," Heinrich said.
Researchers use a "pump-probe" measurement technique, where a fast voltage pulse excites the atom. Then a weaker voltage pulse measures the nature of the atom's magnetism at a certain time after the excitation. The time delay between the two pulses creates a time frame of each measurement. The delay is then varied, and the average magnetic motion is recorded in small time increments. Taken together, the recorded increments give the scientists a more complete picture of the magnetic motion of the atom, similar to how a series of incremental photos can create a motion picture.