A research team led by Dr Alan Drew (University of Fribourg, Switzerland and Queen Mary, London) and Dr Elvezio Morenzoni (Paul Scherrer Institute – PSI, Switzerland) is the first one to have tracked the magnetic processes going on within a hard-drive read head – similar to the heads that read the data off computer hard discs.
In their experiment, the researchers implanted muons into their device. Muons are elementary particles that act like small magnets, and can thus show up the magnetic fields in their surroundings. The muons for this experiment were generated in the particle accelerator at PSI and subsequently subjected to heavy deceleration – PSI is the only location world-wide where this process is available. In the long term, this type of experiment will help us to understand the processes going on inside the read head in greater detail, so that engineers can see where they need to concentrate their efforts to optimise the heads.
The fact that computers can store more data and MP3 players have become so much smaller in the past decade is largely due to an effect that physicists call giant magnetoresistance. In 2007, the Nobel Prize for physics was awarded for the discovery of this effect, which makes it possible to produce electronic components with an electrical resistance extremely sensitive to external magnetic fields. By using the effect in hard drive read heads, magnetically coded information can be packed together very densely, and the hard disc can then be extremely small. Without this effect, it would be impossible for a device half the size of a cigarette packet to store all the information contained in 100 CDs and more.
Original Article from Science Daily
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