Sony has announced a new record of the density of recording on magnetic tape. Together with IBM Research (Zurich), they achieved a density of 201 GB per square inch. This means that on the tape in the standard cartridge TS1155 JD size of 109 × 125 × 24.5 mm will fit not standard 15 TB, but 330 TB of information (taking into account the tape extension by 6.4% due to the reduction of its thickness). What is 330 TB? For example, this is enough to accommodate 3379 compressed copies of all Wikipedia (in all languages). Or 330 million books.
A joint achievement was made possible by an innovative magnetic tape, new lubrication and precise positioning of the magnetic head.
To date, tape drives are the safest, most energy efficient and cheap method of storing large volumes of information for a long time. This is an ideal solution for backups and video archives, for storing information from radio telescopes and the Large Hadron Collider (in fact, they all have no alternative but to store the collected data on tape cartridges). Now the tape finds a new application in the Big Data and as a "cold" store in data centers and cloud services.
IBM writes that tape drives are now experiencing their second youth, and with the new Sony film they will still be relevant long. Although such a film with a nanocoating will be clearly more expensive in production than a conventional tape with a coating of barium ferrite (BaFe).
The new tape consists of several layers of nanoparticles, and the technique of its production somewhat resembles the production of integrated circuits.
The film structure can be considered in more detail under a transmission electron microscope (photo below).
As you can see, the lower layer of the soft CoZrNb substrate (14 nm), as well as the TiCr (2 nm) layer, have an amorphous, chaotic structure, but the fun begins next. The next layer of NiW substrate (10 nm), as well as intermediate ruthenium film layers (this is one material, but it is applied under different conditions, so that two layers are formed) and the actual CoPtCr-SiO magnetic layer 2 (14 nm ) Consist of columnar groups of grains. That's why on the surface of the magnetic layer, a structure similar to bee honeycombs is formed, as seen in the upper photo (in the upper left corner). The width of each "honeycomb" is about 7 nm.
In the end, a reliable protection from a diamond-like carbon nanostructured coating (DLC) 5 nm thick is located above the magnetic layer.
All layers are applied to a polyamide base with a thickness of less than 5 μm. Actually, this is the thickness of this film.
The following illustration shows schematically how these layers are applied in a vacuum chamber. A roll-to-roll method is used, a method of continuously supplying a roll material to deposit materials of a thickness comparable to that of an atom. The process proceeds at room temperature.
The recording and reading of information from such a film would have been impossible, were it not for the new lubrication developed by Sony. The fact is that for recording / reading information with such a density, a very high sensitivity of the head is needed, and therefore it must be extremely close to the tape. In the photo, the image of the head almost merges with its reflection. The invented lubricant effectively reduces the friction between the magnetic head and the film surface, this tightly "sticks" to the magnetic layer.
The role of IBM Research in this work was to develop signal processing algorithms taking into account Principles of noise detection and advanced servo control technologies for positioning the head with an accuracy of 7 nm. Actually, the work of the magnetic head in this tape drive is almost entirely due to IBM Research.
What's the most interesting, 330 terabytes is not the limit. In the video below, Dr. Mark Lantz of IBM Research says that in the future, the density of information on the tape can be further increased.
The presentation of the scientific work of Sony and IBM Research took place on August 2, 2017 at the conference Magnetic Recording Conference (doi: 10.1109 / TMAG.2017.2727822, pdf).