Memory data: transparent magnets will help you record terabytes on analog flash drives

Russia has developed a technology that allows storing large amounts of data on a tiny chip. It is based on the control of the magnetic state of materials using special nanoscale gratings. It can open the way to creating flash drives with a large amount of memory. However, so far the researchers have demonstrated only the physical principle of operation, experts noted. To create real chips, a number of technical challenges will have to be solved, including those related to laser miniaturization, energy consumption, and technology coupling with existing electronics.

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Russian scientists have developed a technology that can become the basis for creating compact and fast computing systems of a new type. It is based on special microstructures that allow using a laser to excite spin waves — fluctuations of magnetic moments — with a length of about hundreds of nanometers. This is ten times less than was previously possible to obtain using optical methods.

The work was attended by specialists from the Russian Quantum Center, Lomonosov Moscow State University, Moscow State Pedagogical University and Vernadsky Crimean Federal University.

— Information can be processed and transmitted in different ways. Electronic is the most common, but it has a number of limitations, such as device heating and a limit on further miniaturization. Among the alternatives is the transmission of a signal using spin waves, that is, fluctuations in the magnetic state of matter. There is reason to believe that with their help, computing operations can become more reliable, economical and faster," Vladimir Belotelov, co—author of the project and head of the scientific group at the Russian Quantum Center, told Izvestia.

He explained that the development of the technology has so far been hampered by the limited focusing size of the laser beam — on the order of several microns. Therefore, the length of the resulting magnetization wave was approximately the same. At the same time, the shorter the wavelength, the denser the logic elements can be placed on the chip.

The scientists solved this problem by coating a transparent magnetic film with a nanoscale lattice. Its pattern works like a template and allows the formation of spin waves with a length of only 0.3 micrometers.

— Previously, the minimum size of the magnetic signal was set by a light beam. Now it is determined by the nanolattice pattern, which forms the desired optical pattern. The smaller this pattern, the shorter the wave and the smaller the component working with it can be. In the experiment, a spin wave with a length of 0.3 microns was obtained, and calculations show that it can be reduced by another three times," said Vladimir Belotelov.

According to him, one of the prospects of the technology is related to new ways of storing data, since spin waves allow the use of an analog recording method. Unlike the traditional digital principle, in which the signal is encoded by a sequence of "zeros" and "ones", in this approach, information is embedded in the parameters of the wave signal. This opens up opportunities for more complex and dense data recording.

— This method is interesting against the background of the development of analog computing. After decades of almost complete digitalization, researchers are once again considering such methods as more effective for solving certain classes of problems. For example, in neuromorphic devices, where information is encoded by continuous signals, rather than discrete "zeros" and "ones," he noted.

Another advantage of such systems may be the high speed of data processing, since spin waves are capable of operating at higher frequencies, the scientist added.

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"The proposed approach opens up new possibilities for controlling magnons—magnetic waves — by designing the pattern of the nanostructure used. The study is unique in its complexity, as it requires high—precision control of a large number of physical processes and parameters during experiments," said Maxim Smirnov, Associate Professor of the Department of Electronics, Quantum Physics and Infocommunication Systems at Kazan National Research Technical University named after A.N. Tupolev — KAI.

In his opinion, the development can contribute to the creation of fundamentally new devices for data storage and processing. They will be able to record terabytes of information in analog form. When solving the issue of a more compact supply of control light pulses, for example, using fiber-optic or nanophotonic systems, the technology can be used in miniature commercial devices.

— In the work, scientists used light to excite spin waves 0.3 microns long, which is several times less than previously obtained by optical methods. This is a significant achievement, but it is natural, since research in this area has been conducted for more than half a century. The foundations were laid in the works of Academician Lev Pitaevsky in the 1960s," said Natalia Istomina, Doctor of Physico-Mathematical Sciences, editor—in-chief of the journal Photonics, professor at the Moscow Aviation Institute and the Moscow State University of Geodesy and Cartography.

There is a change of ideology taking place in the world now — the transition from electron-oriented to photon-oriented systems, she explained. This requires, in particular, interface elements. The world's leading microelectronics developers and manufacturers are already moving in this direction, including in Russia.

According to the expert, with the introduction of such devices, many things in their design should change. For example, there are already tools for fast transmission of information over optical fiber, but their use is limited by the problem of interfacing with an electronic component base. Switches are currently being created for these purposes. The presented development can find application in this direction as well.

— In scientific terms, a significant and, to a certain extent, breakthrough result has been achieved. At the same time, it is more correct to talk about demonstrating a new physical principle, whereas the creation of memory and processors based on it will be the next stage of research," said Dmitry Chermoshentsev, a scientist at the Russian Quantum Project and an assistant at the Department of the Phystech School of Physics and Research named after Landau at the Moscow Institute of Physics and Technology.

In the future, scientists will have to reduce the wavelength to the estimated 100 nm, reduce attenuation and combine the processes of signal generation and reading on a single chip. For practical application, it is also important to evaluate energy consumption and demonstrate the sustainable performance of individual operations.

In his opinion, the proposed approach can become the basis for elements of superdense magnetic memory if it is possible to link the excitation of spin waves with reliable switching of stable magnetic states. In addition, the development may find application in the creation of magnon filters, compact devices for cleaning the radio signal.