Sometimes I step onto a research result that is so incredible to make me think that it couldn’t have been imagined by science fiction and this is one of such cases.
Researchers at the Berkeley Lab are investigating ways of exploiting whirlpools at the nanoscale to create devices that can perform 100 times better than current ones in terms of power consumption and storage density.
Magnetic memory are based on the spin of the electrons. When you align the spin of many electrons in a specific area you get a magnetic field, by changing their spin you change the magnetic field and this is what is being used to store bits in a magnetic memory. All atoms have electrons and certain kind of atoms (the so called ferromagnetic materials) are easier to influence and therefore one can set their spin as desired (using a magnetic field).
What Berkeley Lab researchers did was to create a nanometric structure where the electromagnetic field creates a nanometric whirlpools having peculiar magnetic properties.
As shown in the figure on the left you can imagine having a disk 20 nm thick and 100 nm across spinning in one or the other direction. It is just for the sake of imagination, actually there is not such a disk but only a material made of atoms clustered in such a way that electrons rotate that way. Additionally, electrons have a spin (up or down) that generates a magnetic field (-+).
The material is structured in such a way to generate whirlpools of magnetic field that can therefore have four different states, (+, -, clockwise, counterclockwise). Since it can have four states one can store 2 bits.
The researchers have found the way to create such structure and to use magnetic pulses to “write” a specific state (and then to “read” it). The first structure was bigger, 30 nm thick and a thousand nm across, and although it worked the switching time from one state to the other was too long (relatively speaking…. since it took 3 ns!). By decreasing the size they have achieved a switching speed of half a ns (in that time frame a light ray moves 1.5 cm).
The problem researchers are still facing is that so far they have been able to sea between up and down spin or clockwise and counterclockwise but are not able to swap both at the same time. It would be like saying that you can write a 3 if you have a 1 or you can write a 2 if you have a 0 but you cannot write a 3 if you have a 0…. Obviously that is not good!
However, they feel that it will be just a matter of few more tweakings and a complete manipulation of the whirlpools will become possible.
We are, clearly, at the forefront of science, its practical application is not in sight but the discovery of these whirlpools, their properties, how to create them and how to exploit them identifies a possible path of evolution and usually that is what you need to stimulate innovation.