Multiferroic compounds used to produce smaller and cheaper digital memories

November 27, 2009
Image of the ferroelectric domains of the multiferroic compound BiFeO3. © A. Mougin, CNRS 2009

( -- Is it possible to make even more compact digital memories for portable electronic devices and which consume even less energy? A team of French researchers has recently demonstrated that it is feasible, thanks to a new class of materials known as multiferroics, which combine unusual electric and magnetic properties.

At a microscopic scale, atoms and produce electric and magnetic fields. At our own scale, in the majority of , the electric and of the various atoms offset one another and cancel each other out. Sometimes, however, this is not the case and in certain compounds, known as ferromagnetics, magnetic properties subsist at a macroscopic scale and can therefore act as a magnet.

Less commonly, an electric order can exist at the macroscopic scale; such is the case with what are known as ferroelectric compounds. Even more rarely, electric and magnetic orders exist at one and the same time, as is the case with multiferroic materials. Moreover, in these materials, the electric and magnetic orders interact. Such interaction offers the opportunity of controlling the spins (the magnetic moments) of the via an electric field, thus opening whole new perspectives particularly as regards information storage.

Researchers at the Laboratoire de Physique des Solides, the Institut Rayonnement-Matičre de Saclay and the Institut Néel first synthesized the multiferroic compound BiFeO3 and then demonstrated the interaction between its electric and magnetic orders. They then produced a material formed of a layer of BiFeO3 and a ferromagnetic film and showed that they were able to modify the preferential orientation of the magnetization of the ferromagnetic film by applying an electric field. These pioneering results validate the concept of storing and writing magnetic data using an electric field.

In today's hard discs, data - or bits - are written using a magnetic field that directs the magnetization, which imposes the bit value. There are two possible magnetization states and thus two possible bit values (designated 0 or 1). With a multiferroic material, each memory element could be placed in four distinct states instead of two (two electrical polarization states and two magnetization states). Magnetic memories with two states (like existing memories), but which can be modified through the application of an electric field, could also be envisaged.

This possibility of writing and erasing data using an electric field constitutes a decisive advantage in mobile (mobile phones, laptop computers, GPS, etc.) from two points of view. Firstly, the application of an electric field requires less energy than the application of a magnetic field and therefore batteries would last longer. Secondly, the electric field would be more local, which would mean more memory elements could be packed onto a given surface and thus enable component miniaturization to be pushed even further.

More information: switching of the anisotropy of a ferromagnetic layer exchange coupled to the multiferroic compound BiFeO3. D. Lebeugle, A. Mougin, M. Viret, D. Colson, L. Ranno. Physical Review Letters, 18 November 2009.

Provided by CNRS

Explore further: New memory storage devices on horizon with award-winning work

Related Stories

Magnetic Vortex Switch Leads to Electric Pulse

April 8, 2009

( -- Researchers at the University of Arkansas have shown that changing the chirality, or direction of spin, of a nanoscale magnetic vortex creates an electric pulse, suggesting that such a pulse might be of use ...

Electric Switches Hold Promise for Data Storage

May 22, 2009

( -- Multiferroics are materials in which unique combinations of electric and magnetic properties can simultaneously coexist. They are potential cornerstones in future magnetic data storage and spintronic devices ...

Creating Denser Magnetic Memory

July 7, 2009

( -- One of the issues afflicting magnetic memory is the fact that it is difficult to store information for as long as 10 years. In order to overcome this problem, scientists and engineers have been looking for ...

Recommended for you

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

Exploring the physics of a chocolate fountain

November 24, 2015

A mathematics student has worked out the secrets of how chocolate behaves in a chocolate fountain, answering the age-old question of why the falling 'curtain' of chocolate surprisingly pulls inwards rather than going straight ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Nov 28, 2009
4 bits instead of 2 is like 8 values instead of 2 per domain ? Does that mean with same densities we will have 16 TB Harddisks soon?

Even more important, this could make affordable 500+ GB SSD within reach of the consumer, because bits per cell has been much more of a prohibiting costfactor for SSD than HD platters.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.