High density storage future stretches ahead

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A “pretty boring” oxide has been converted into a stunning material that could hold the secret for a future generation of storage devices.

A Cornell University research team dubbed the compound as dull in an article in Nature magazine but the implications are stirring up a lot of excitement.

This ugly duckling compound is europium titanate which displays incredible magnetic properties when correctly processed. A thin nanoscale layer of the oxide is stretched on a substrate of another oxide, dysprosium scandate, to create the right conditions.

The europium titanate then reveals its majestic properties as a substance that simultaneously possesses electronic polarisation (ferroelectric) and a permanent magnetic field (ferromagnetic). It is also 1,000 times more effective than any other known compounds with similar properties.

The electrical and magnetic polarity can be manipulated to form the basis for low-power, highly sensitive magnetic memory, magnetic sensors or finely-tuneable microwave devices.

"Our strategy is to use first-principles theory to look among materials that are neither ferromagnetic nor ferroelectric, of which there are many, and to identify candidates that, when squeezed or stretched, will take on these properties," said researcher Craig Fennie, assistant professor of applied and engineering physics at Cornell.

There are two serious drawbacks to the research. One is that the experiment was conducted at an incredibly low temperature of about four degrees Kelvin (-269 Celsius). The other is that current pricing for the oxide is £72 per gram.

The team is now working on materials they predict will show similar multiferroic properties at much higher temperatures. After this, the mechanics of how to store data on the new medium will have to be devised so it could be many years before the benefits can be realised.

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