Computer files that allow us to watch videos, store pictures, and edit all kinds of media formats are nothing else but streams of "0" and "1" digital data, that is, bits and bytes. Modern computing technology is based on our ability to write, store, and retrieve digital information as efficiently as possible. In a computer hard disk, this is achieved in practice by writing information on a thin magnetic layer, where magnetic domains pointing "up" represent a "1" and magnetic domains pointing down represent a "0".
The size of these magnetic domains has now reached a few tens of nanometers, allowing us to store a Terabyte of data in the space of just a few square centimeters. Miniaturization, however, has created numerous problems that physicists and engineers worldwide struggle to solve at the pace demanded by an ever-growing information technology industry. The process of writing information on tiny magnetic bits one by one, as fast as possible, and with little energy consumption, represents one of the biggest hurdles in this field.
A team of scientists from the Catalan Institute of Nanotechnology, in collaboration with SPINTEC researchers in France, has discovered a new method to write magnetic data that meets all of these requirements. Magnetic writing is currently performed using magnetic fields produced by wires and coils, a methodology suffering severe limitations in scalability and energy efficiency. The new technique eliminates this and provides extremely simple and reversible writing of memory elements by injecting an electric current parallel to the magnetic layer. The key to this effect lies in engineering a magnetic cobalt film less than one nanometer thick sandwiched between platinum and aluminum oxide. The research team showed that using current pulses that last less than 10 ns produced magnetic switching reliably at room temperature, while further miniaturization and faster switching appear easily within reach.
This work has interesting applications for the magnetic recording industry, in particular the development of magnetic random access memories (MRAMs). By replacing standard RAMs, which need to be refreshed every few milliseconds, non-volatile MRAMs would allow instant power up of a computer and also save a substantial amount of energy. An additional advantage of the technique is that it is more efficient in "hard" magnetic layers that can be more easily miniaturized to nanometer dimensions, resulting in significantly increased information storage density. Three patent applications de