OPTIMAS researchers demonstrate information processing by spin waves in prototypical device
Electrons play a crucial role in the processing of information. However, as electronic devices get smaller and more powerful, electric current is reaching its limit due to its high heat dissipation. Therefore current research aims to find alternative technologies such as the use of spin waves. Researchers from the state research center OPTIMAS at the University of Kaiserslautern were now able to process information using spin waves in a special device (a so-called logic gate) for the first time. Such technology offers the potential to improve the speed and efficiency for processing and transmission of data in the future and replace conventional semiconductor technology. The study has been published in the journal “Applied Physics Letters”.
Electric current does not satisfy future technologic requirements. A promising alternative are spin waves. “Spin is the inherent angular momentum of a quasiparticle, such as an electron or proton”, says PhD candidate Tobias Fischer, who is the first author of the study. “It is the basis for all magnetic phenomena.” The quantum particles of spin waves – the magnons – are able to transport much more information than electrons while consuming less energy and thus less heat dissipation. This makes spin waves interesting for applications.
Fischer studied for the first time if spin waves can be used in logic gates for information processing. Conventional logic gates are based on electric current and are used e.g. in computers by combining transistors. Information in such a device is encoded in the states “0” and “1”.
The device by the researchers from Kaiserslautern is formed as a trident and is made of the magnetic material yttrium-iron garnet. “Spin waves are excited in each of the three tips of the trident. The information is encoded in the phase of the wave and the relative phase of the three waves determines the output.”, Fischer describes. All waves travel along the three tips similar to a wave in a football stadium. In the connection of the trident all waves then superimpose. “The position of valleys and peaks of the wave are shifted by interference of the waves”, says Dr. Andrii Chumak, co-author of the study. “This information – the so-called phase shift – can be read out.” The co-workers of Fischer studied such waves already by simulations and the PhD candidate now succeeded in realizing the experiment.
Fischer and Chumak are researches of the magnetism group of Professor Dr. Burkard Hillebrands at the University of Kaiserslautern (state research center OPTIMAS). The work was carried out within the collaborative research center SFB/TRR 173 “Spin+X – Spin in its collective environment”, where research teams in physics, chemistry, and process and material engineering investigate fundamental magnetic properties, phenomena and processes. Such properties are already today crucial for modern technology such as data storage and magnetic sensing.
Chumak received an ERC starting grant – one of the highest ranked awards for research from the European Union – for his work on the field.
The study has been published in the journal “Applied Physics Letters“:
"Experimental prototype of a spin-wave majority gate" T. Fischer, M. Kewenig, D. A. Bozhko, A. A. Serga, I. I. Syvorotka, F. Ciubotaru, C. Adelmann, B. Hillebrands, and A. V. Chumak (DOI: 10.1063/1.4979840).
http://aip.scitation.org/doi/full/10.1063/1.4979840
Contact persons:
Tobias Fischer, Dipl.-Phys.
Magnetism group, Department of Physics
Phone: 0631 205-2278
E-Mail: tfischer[at]physik.uni-kl.de
Dr. Andrii Chumak
Magnetism group, Department of Physics
Phone: 0631 205-4203
E-Mail: Chumak[at]physik.uni-kl.de
Marjorie Lägel
Magnetism group, Department of Physics
Phone: 0631 205 5779
E-mail: mlaegel[at]rhrk.uni-kl.de