Magnetic breakthrough
16 Feb 2012 by Evoluted New Media
A revolutionary new way of magnetic recording could open the door for faster information processing.
An international team of scientists has discovered that heat can be used to record information on a magnetic medium – a scenario previously thought impossible.
[caption id="attachment_26696" align="alignright" width="200" caption="Before the laser pulse, the two components of the ferrimagnetic material Fe (Blue) and Gd (Red) are aligned anti-parallel to each other. The 60 femtosecond duration laser pulse rapidly heats the material and this alone induces a transient ferromagnetic-like state, where the Fe and Gd moments are aligned in parallel. After the laser pulse the moments relax to their usual state completing a single switching event in less than 5 picoseconds Credit: Richard Evans, University of York"]
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Current magnetic recording technology works on the basis that the North pole of a magnet is attracted to the South, and repelled by the North. In order to record one bit of information – achieved by inverting the poles if the magnet – it was thought you needed to apply a magnetic field, a spin polarised electric current or a cross product of two oscillating electric fields.
“For centuries it has been believed that heat can only destroy the magnetic order,” said Dr Alexy Kimel from the Institute of Molecules and Materials, Radboud University Nijmegen. “Now we have successfully demonstrated that it can, in fact be a sufficient stimulus for recording information on a magnetic medium.”
The team – which included researchers from the University of York – found that the positions of both poles of a magnet can be inverted by an ultrashort heat pulse without the presence of a magnetic field.
[caption id="attachment_26699" align="alignleft" width="200" caption=" The ultimate magnetic storage medium, consisting of many individual nanometre sized magnetic grains with a density of 10 petabytes/m^2. The data is written to the device using an ultrafast heating process to drive the reversal at a data rate of 200Gb/s Credit: Richard Evans, University of York"]
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“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,” said Thomas Ostler, a physicist from York. “This revolutionary method allows the recording of Terabytes of information per second, hundreds of times faster than present hard drive technology.”
Researchers believe this discovery will make future magnetic recording device faster and more energy-efficient too. Ostler said that since no magnetic field is necessary, energy consumption is reduced.
