# 12 atoms per bit vs 35 bits per electron

Read a story today in Technology Review on Magnetic Memory Miniaturized to Just 12 Atoms by a team at  IBM Research that created a (spin) magnetic “storage device” that used 12 iron atoms  to record a single bit (near absolute zero and just for a few hours).  The article said it was about 100X  denser than the previous magnetic storage record.

## Holographic storage beats that

Wikipedia’s (soon to go dark for 24hrs) article on Memory Storage Density mentioned research at Stanford that in 2009 created an electronic quantum holographic device that stored 35 bits/electron using a sheet of copper atoms to record the letters S and U.

The Wikipedia article went on to equate 35bits/electron to ~3 Exabytes[10**18 bytes]/In**2.  (Although, how Wikipedia was able to convert from bits/electron to EB/in**2 I don’t know but I’ll accept it as a given)

Now an iron atom has 26 electrons and copper has 29 electrons.  If 35 bits/electron is 3 EB/in**2 (or ~30Eb/in**2), then 1 bit per 12 iron atoms (or 12*26=312 electrons) should be 0.0032bits/electron or ~275TB/in**2 (or ~2.8Pb/in**2).   Not quite to the scale of the holographic device but interesting nonetheless.

## What can that do for my desktop?

Given that today’s recording head/media has demonstrated ~3.3Tb/in**2 (see our Disk drive density multiplying by 6X post), the 12 atoms per bit  is a significant advance for (spin) magnetic storage.

With today’s disk industry shipping 1TB/disk platters using ~0.6Tb/in**2 (see our Disk capacity growing out of sight post), these technologies, if implemented in a disk form factor, could store from 4.6PB to 50EB in a 3.5″ form factor storage device.

So there is a limit to (spin) magnetic storage and it’s about 11000X larger than holographic storage.   Once again holographic storage proves it can significantly store more data than magnetic storage if only it could be commercialized. (Probably a subject to cover in a future post.)

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I don’t know about you but 4.6PB drive is probably more than enough storage for my lifetime and then some.  But then again those new 4K High Definition videos, may take up a lot more space than my (low definition) DVD collection.