"Superhero" compound could spark next-gen storage

 

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By Stewart Mitchell

Posted on 19 Aug 2010 at 12:09

Scientists believe they have uncovered the Peter Parker of oxide compounds, a superhero material that could revolutionise electronics and computing components.

According to researchers at Cornell University in the US, europium titanate is a dull compound with no exciting attributes until it is sliced thinly and stretched.

Then, it takes on rare and useful properties. Nanoscale-thin films of europium titanate become both ferroelectric (electrically polarised) and ferromagnetic (exhibiting a permanent magnetic field) when stretched across a substrate of dysprosium scandate, another type of oxide.

Simultaneous ferroelectricity and ferromagnetism is rare in nature and coveted by electronics visionaries. Because of the potential for manipulating both the electrical and magnetic polarity, materials with this magic combination could form the basis for low-power, highly sensitive magnetic memory, magnetic sensors or finely-tunable microwave devices.

Although other compounds display this rare polar double whammy, the nearest competitor in terms of performance - nickel boracite - pales in comparison, with effectiveness reduced by a factor of 1,000.

"Previous researchers were searching directly for a ferromagnetic ferroelectric – an extremely rare form of matter," said Darrell Schlom, Cornell professor of materials science and engineering on the project.

"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.”

Despite the early promise, commercial devices remain a long way off partly because the initial experiments required extremely cold temperatures - 4 degrees Kelvin, or -269C - to work.