There is a saying that the amount of data always grows until it fills all the available space. Perhaps twenty years ago, it was commonplace to store software, MP3 music, movies, and other files on a computer that could have accumulated over the years. In those days, when hard drives could hold tens of gigabytes of memory, they almost inevitably ended up overflowing.
Now that fast broadband internet is available and we don't even think about downloading a 4.7GB DVD, data storage is even faster. The total amount of data stored on computers worldwide is estimated to grow from 4.4 trillion gigabytes in 2013 to 44 trillion in 2020. This means that on average we generate approximately 15 million gigabytes per day. Even though hard drives are now measured in thousands of gigabytes rather than tens, we still have a storage problem.
Much research and development is devoted to finding new ways to store data that would allow for greater density and thereby store more information with greater energy efficiency. Sometimes this is due to the updating of familiar and well-known methods. For example, IBM recently announced a new technology. Their magnetic tape is capable of storing 25 gigabytes of information per square inch (about 6.5 square centimeters) - a new world record for a technology that's sixty years old. Although today's solid state hard drives have a higher density, around 200 gigabytes per square inch, magnetic tapes are still commonly used for backing up data.
However, modern research in the field of data storage is already dealing with individual atoms and molecules, which is objectively the last limit of technological miniaturization.
Monatomic and mono-molecular magnets do not need to communicate with neighboring ones in order to maintain their magnetic memory. The point is that here the memory effect arises from the laws of quantum mechanics. Because atoms or molecules are much smaller than currently used magnetic domains and can be used individually rather than in groups, they can be "packed" more tightly, which could lead to a giant leap in data density.
This kind of work with atoms and molecules is no longer science fiction. The effects of magnetic memory in single-molecular magnets were first discovered back in 1993, and similar effects for single-atomic magnets were demonstrated in 2016.
The main problem facing these technologies from the laboratory to mass production is that they do not yet work at normal ambient temperatures. Both single atoms and single-molecular magnets require cooling with liquid helium (up to a temperature of - 269 ° C), and this is an expensive and limited resource. However, recently, a research group at the University of Manchester School of Chemistry achieved magnetic hysteresis, or the appearance of a magnetic memory effect, in a single-molecule magnet at - 213 ° C using a new molecule derived from rare earth elements, as reported in their letter to the journal Nature. Thus, having made a jump of 56 degrees, they were only 17 degrees from the temperature of liquid nitrogen.
However, there are other problems as well. In order to actually store individual bits of data, the molecules must be fixed to surfaces. This has already been achieved with single-molecule magnets in the past, but not for the latest generation of high temperature magnets. At the same time, this effect has already been demonstrated on single atoms fixed on the surface.
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The ultimate test is the demonstration of non-destructive reading of information from individual atoms and molecules. This goal was achieved for the first time in 2017 by a team of researchers from IBM, which demonstrated the smallest magnetic storage device built on the basis of a monatomic magnet.
However, irrespective of whether or not monatomic and single-molecular memory devices will actually be applied in practice and become widespread, the achievements of fundamental science in this direction cannot be denied simply phenomenal. Synthetic chemistry methods developed by research groups working with single-molecule magnets allow today to create molecules with individual magnetic properties that will find application in quantum computing and even in magnetic resonance imaging.
Igor Abramov