Boffins Invent Nano-scale Ultra-density Memory
A joint project by researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory and the University of California Berkeley has led to the invention of what is potentially the world’s highest density memory. The nano-tube archival memory boasts of the ability to store data to a density of trillion bits/square inch and can retain this data for a billion years.
Reported in the journal Nano Letters, the nano-tube archival memory is still only in its theoretical mode and years away from practical use. The system is based on a nano-scale iron particle that is 1/50,000 times the width of a human hair travelling inside a carbon nano-tube. The particle would be frozen in position inside the nano-tube until an electric current is applied.
Depending on the current source, the iron particle would either be attracted towards it or repelled. Researchers managed to get the particle to move in fixed 3nm distance blocks by applying the current in a timed pulse, with the speed controlled through the bias voltage.
Employing a technology similar to that used for semiconductor manufacturing, researchers used a single step pyrolysis of ferrocene in argon at 1,000 degrees C for creating the nano-tube. Ultrasound was used to first disperse the resultant tube in isopropanol and then deposit it on a substrate that allowed electric current to be applied to both ends of the nano-tube.
According to researchers, achieving digital one or zero in the system is a simple process of positioning the iron particle shuttle on either side of the length-wise mid-point of the nano-tube. The exact location of the particle could be checked by sending small voltage pulses through the nano-tube and reading the axial electrical resistance produced. The extremely small voltage pulses would not change the position of the shuttle but would betray its location.
To get an idea about the how the data value could be changed, the researchers determined the minimum distance the particle would have to travel without application of voltage. They also calculated that the time required for the data value to change as 3.3 x 10 to the power 17 seconds.
Theoretical extrapolation then allowed the researchers to deduce that the storage memory element can act as an archive with a billion year lifespan. In the same manner, the researchers calculated that the iron particle – nano-tube chip would have the capacity to store one trillion bits of data in a square inch of space.
Though decades away from commercial application and use, the research does open up fantastic new options in memory storage and could pave the path to development of future nano-scale but high density storage applications.