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IBM Makes Tiny (Though Impractical) 12-Atom Magnetic Bit

The technology extends the range of magnetic memory, but it's unlikely to make it into hard drives anytime soon

2 min read
IBM Makes Tiny (Though Impractical) 12-Atom Magnetic Bit

A team at IBM Research Almaden in San Jose, California has shown they can store data in bits that contain just 12 atoms. These may very well be the smallest magnetic memory bits ever constructed. But the advance seems pretty far away from practical devices.

IBM's Andreas Heinrich and colleagues made the bits out of two side-by-side rows of iron atoms with alternating magnetization. Bits can be switched from one alternating configuration (Left-Right-Left..., for example, to Right-Left-Right...) using the polarized tip of a scanning tunneling microscope. The state of the bit can be measured using the same microscope tip by exploiting magnetoresistive tunneling (electrons will tunnel differently depending on whether or not the tip and atom spins are parallel or antiparallel).

Today's hard drives have bits that contain a million or so atoms. Each has a net magnetization that makes it susceptible to stray magnetic fields. The team says the alternating configuration (which gives each bit zero net magnetization) allow them to place magnetic bits closer together with little interference.

A video put together by IBM (embedded below) suggests this advance could pave the way to denser magnetic storage devices, but I'm a bit skeptical (and so is Heinrich, it seems). For one thing, the team needed a scanning tunneling microscope in order to place the bits. The atoms also needed to be cooled down to just a few degrees above absolute zero to cut down on the thermal fluctuations that can easily wipe a bit.

This second issue -- thermal energy -- places limits on how small individual bits can be and still work at room temperature. For conventional hard disks, the individual grains that make up a single bit become unstable when they're smaller than about 6 nanometers, roughly the size of the bits that IBM made.

I recently spoke with researchers at Hitachi, who are considering a few work-arounds. One is to use materials that can more easily resist attempts to change magnetization. These bits would be difficult to write at room temperature and would thus need to be hit with a laser. But this technology is still likely years away from making into production.

Even Heinrich believes tiny scanning tunneling microscope-built devices "would never be more than laboratory experiments", according to The New York Times. That said, antiferromagnetism is making inroads in other ways: the Times cites hard disk write heads and one potential, next-generation memory: spin-torque-transfer RAM. This experiment shows what antiferromagnetism can do when it's pushed to the limit. It will be exciting to see how it can extend into our everyday lives.

(Image: Sebastian Loth, IBM Research/Almaden)

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Why Functional Programming Should Be the Future of Software Development

It’s hard to learn, but your code will produce fewer nasty surprises

11 min read
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A plate of spaghetti made from code
Shira Inbar
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You’d expectthe longest and most costly phase in the lifecycle of a software product to be the initial development of the system, when all those great features are first imagined and then created. In fact, the hardest part comes later, during the maintenance phase. That’s when programmers pay the price for the shortcuts they took during development.

So why did they take shortcuts? Maybe they didn’t realize that they were cutting any corners. Only when their code was deployed and exercised by a lot of users did its hidden flaws come to light. And maybe the developers were rushed. Time-to-market pressures would almost guarantee that their software will contain more bugs than it would otherwise.

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