An elastic transparent composite has been created that can be used in the production of HAMR drives

    Welcome to our readers on the iCover Blog Pages ! A group of scientists from ITMO University and the Hebrew University of Jerusalem has developed a technology for creating a transparent and flexible magnetic film that can be used in the production of flexible displays, as a means of protection against electromagnetic radiation and in other promising areas. The material obtained at normal pressure and room temperature has pronounced magnetic properties and thermal conductivity, which, according to scientists, will allow its use in the production of HAMR-drives. The results of the collaboration were published in the Journal of Materials Chemistry C.


    About development

    The basis of the three-component composition from which the film was obtained is magnetite, to which silver nanowires are added in a volume of 10% and a crosslinking agent in a volume of 5%. Silver nanowires impart electrically conductive properties to the material, magnetite nanoparticles - magnetic, and alumina, used as a crosslinking agent, allows the entire structure to remain stable. The process of material synthesis is carried out using the sol-gel method based on an alcohol solution. To prevent uneven accumulation of particles of the composition and precipitation, an author's technology was proposed that ensures the uniformity of the charge of particles throughout the volume of the solution. According to the head of the laboratory “Solution chemistry of advanced materials and technologies” ITMO and, in combination, the project managerVladimir Vinogradov : "... Analogues of magnetic conductive materials with such a set of properties do not exist today."

    “The key task that our group solved was the synthesis of a multifunctional material from magnetic nanoparticles. It is extremely difficult to obtain a stable colloidal system from magnetite nanoparticles while maintaining neutral pH values, since such particles, at a neutral pH value, have the ability to accumulate or precipitate. One solution is to stabilize the mixture with polymers or surfactants, or to protonate with hydrogen, but this will inevitably lead to a very acidic environment and dissolves silver nanowires, ”Vladimir described the main problem of the experiment.

    Advantages of the proposed solution

    Technologically, the solution looks like this: in the process of spraying the solution, the alcohol evaporates, and silver threads, magnetite nanoparticles and aluminum oxide are combined in a single structure. In this case, it is extremely important that the spraying is carried out under normal conditions and a temperature of 25 degrees Celsius - that is, as simple as if we sprayed ordinary paint. Compared with the technology proposed by the Vinogradov group, the method of spraying expensive conductive indium onto a brittle polymer substrate used for similar purposes is much more complicated and expensive.

    In addition, the technology using indium limits the possibility of bending the material by an angle of 30-40 degrees, because when this threshold value is overcome, the resulting composite avalanchely loses its conductivity. Moreover, at an indium cost of $ 1,000 per kilogram, the spraying process should be carried out under extremely harsh conditions - inside a vacuum chamber using expensive auxiliary equipment, which casts great doubt on the economic feasibility of such a solution.

    Another development advantage that you need to pay attention to is the ability of the resulting material to provide effective protection against electromagnetic radiation. And such an advantage, in particular, is already in great demand today in the military-industrial complex. Moreover, at the moment, this area of ​​application of analogous materials is almost 80% percent involved in the defense order.

    Vladimir Vinogradov

    So, we can say that the key advantages of the composite obtained are a combination of such valuable advantages as the relatively low cost of a ready-made solution, the possibility of using it in several promising directions at once, the ability to organize production at normal atmospheric pressure and room temperature, which, again, significantly reduces the cost of its manufacture, such qualities as flexibility and transparency.

    Particular attention should be paid to the prospect of using such a flexible transparent magnetic film when creating HAMR drives, because, as Vinogradov emphasized in his interview: “... By its magnetic and thermally conductive properties, our material is not only ideal for use in the manufacture of HAMR drives, but also allows make storage media flexible and transparent. ”

    Quick reference: HAMR is a hybrid information recording technology that combines the capabilities of magnetic reading and magneto-optical recording. The principle of operation of devices using HAMR involves local laser heating of the recording zone to 100 ° C in 1 ps, which increases its magnetic properties and leads to magnetization reversal of this area. Thus, the size of the magnetic region, which is able to store one bit of information is significantly reduced, its storage density is proportionally increased and the influence of the superparamagnetic effect is reduced.

    Note that at Seagate, the development of HAMR technology began back in 1998. At the IEEE International Magnetics Conference 2015 ( InterMag) Seagate demonstrated a working prototype of a storage system equipped with disks that used thermomagnetic recording technology. And at the same time, despite some successes, the beginning of the commercial production of HAMR-based discs by Seagate dates back to 2017–2018, although it was previously planned to introduce the first products in 2016. The next postponement is associated with the cornerstone problem: obtaining sufficiently stable operating characteristics of the created systems in the long term.

    At the initial stage, the company plans to deliver HAMR disks to priority customers in test mode in the first quarter of 2017, and it will most likely reach full-scale commercial production not earlier than 2018. You can only guess about the price of the solution.

    We wish the group of Vladimir Vinogradov success in promoting their material on the commercial market and we hope that the results obtained in the laboratory can be confirmed at the level of commercial products in the very near future.

    Sources used in this article:

    Journal Journal of Materials Chemistry C

    Press Service of the University ITMO

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