Heat-based recording speeds hard drives

Posted by Emma Woollacott

A new method of recording information to hard drives could increase their speed by hundreds of times.

An international team has found, astonishingly, that it's possible to record information using only heat – making future magnetic recording devices not only faster, but more energy-efficient too.

"Instead of using a magnetic field to record information on a magnetic medium, we harnessed much stronger internal forces and recorded information using only heat," says University of York physicist Thomas Ostler.

"This revolutionary method allows the recording of Terabytes (thousands of Gigabytes) of information per second, hundreds of times faster than present hard drive technology. As there is no need for a magnetic field, there is also less energy consumption."  

The discovery is all the more of a surprise given that, until now, it's always been believed that heat would simply destroy the magnetic order.

Modern magnetic recording technology is based on the fact that the north pole of a magnet is attracted to the south pole of another, and that two like poles repulse.

Recording a bit of information involves magnetizing a tiny part of the magnetic medium either 'up' or 'down' – and it's always been assumed that to do this, it's necessary to apply an xternal magnetic field.
The stronger the applied field, the faster the recording of a magnetic bit of information. 

However, the new research shows that the positions of both the north and south poles of a magnet can be inverted by an ultrashort heat pulse.

The pulse manages this by harnessing the power of much stronger internal forces of magnetic media. In the material the team used - an alloy of gadolinium and iron - the two types of atom are magnetized in opposite directions.

The laser light heats the material up so fast that, at first, only the iron atoms lose their magnetization, and align theimselves with the gadolinium. When the material cools, the iron atoms reverse their magnetism again.

Eliminating the need for an electromagnet makes it a much more efficient technique.