A team of scientists, including physicists from MIPT and the Russian Quantum Centre, have demonstrated a method of exciting magnetic vortices – which could potentially be used in the electronics of the future as information carriers – using less current. The corresponding theoretical calculations have been publishedin Physical Review B.
Magnetic vortices are microscopic areas of magnetized material with uniquely arranged magnetization vectors. In the centre of the vortex, the magnetization vector is oriented perpendicularly to the surface, and at the edges these vectors form a structure resembling a vortex or whirlpool. An example of a magnetic vortex is shown in the illustration above.
The magnetization vector is in turn linked to spin, a quantum characteristic of individual particles. Controlling magnetic vortices, through spin or otherwise, is what scientists are researching as a foundation for the electronics of the future – spintronics. In order to store and process information in spintronics, the movement of electrons from one position to another or the flow of electronic charges is not important – what is most important is spin and the movement of electrons with a certain spin, a spin current. Information can be transmitted by spin rather than electronic charge, and the charged particles do not necessarily need to move anywhere – they can remain in the same position, but their spins will rotate, transmitting information “along the chain”.
Using spin to transmit a unit of information is very interesting because the processing (e.g. changing 0 to 1 in binary code through one spin revolution) requires much less time and energy than a similar operation in modern electronics. Microchips operating with electron spin will heat up less and a number of calculations also demonstrate that they will be less sensitive to radiation. Spintronics stands a good chance of replacing many common devices, but for this to happen, scientists will first need to address a number of fundamental and practical issues.
Spintronics will require new methods of storing and processing information. Magnetic vortices could potentially be a solution – they can be used both to store information (0 – spin clockwise, 1 – spin anti-clockwise, or 0 – core magnetized up, 1 – magnetized down) and process information – different vortices interact differently with the spin current (a flow of electrons, in which the largest portion is made up of electrons with a certain spin), which will make it possible to build complex devices and even artificial neural networks. These vortices will also be able to be used to create AC nanogenerators, which could potentially be used in telecommunication applications.
