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Researchers 'stretch' a lackluster material into a possible electronics revolution
Cornell University ^ | August 18, 2010 | Unknown

Posted on 08/18/2010 12:33:43 PM PDT by decimon

ITHACA, N.Y. — It's the Clark Kent of oxide compounds, and – on its own – it is pretty boring. But slice europium titanate nanometers thin and physically stretch it, and then it takes on super hero-like properties that could revolutionize electronics, according to new Cornell research. (Nature, Aug. 19, 2010.)

Researchers report that thin films of europium titanate become both ferroelectric (electrically polarized) and ferromagnetic (exhibiting a permanent magnetic field) when stretched across a substrate of dysprosium scandate, another type of oxide. The best simultaneously ferroelectric, ferromagnetic material to date pales in comparison by a factor of 1,000.

Simultaneous ferroelectricity and ferromagnetism is rare in nature and coveted by electronics visionaries. A material with this magical combination could form the basis for low-power, highly sensitive magnetic memory, magnetic sensors or highly tunable microwave devices.

The search for ferromagnetic ferroelectrics dates back to 1966, when the first such compound – a nickel boracite – was discovered. Since then, scientists have found a few additional ferromagnetic ferroelectrics, but none stronger than the nickel compound – that is, until now.

"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, and an author on the paper.

"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 Craig Fennie, assistant professor of applied and engineering physics, and another author on the paper.

This fresh strategy, demonstrated using the europium titanate, opens the door to other ferromagnetic ferroelectrics that may work at even higher temperatures using the same materials-by-design strategy, the researchers said.

Other authors include David A. Muller, Cornell professor of applied and engineering physics; and first author June Hyuk Lee, a graduate student in Schlom's lab.

The researchers took an ultra-thin layer of the oxide and "stretched" it by placing it on top of the disprosium compound. The crystal structure of the europium titanate became strained because of its tendency to align itself with the underlying arrangement of atoms in the substrate.

Fennie's previous theoretical work had indicated that a different kind of material strain – more akin to squishing by compression – would also produce ferromagnetism and ferroelectricity. But the team discovered that the stretched europium compound displayed electrical properties 1,000 times better than the best-known ferroelectric/ferromagnetic material thus far, translating to thicker, higher-quality films.

This new approach to ferromagnetic ferroelectrics could prove a key step toward the development of next-generation memory storage, superb magnetic field sensors and many other applications long dreamed about. But commercial devices are a long way off; no devices have yet been made using this material. The Cornell experiment was conducted at an extremely cold temperature – about 4 degrees Kelvin (-452 Fahrenheit). The team is already working on materials that are predicted to show such properties at much higher temperatures.

###

The team includes researchers from Penn State University, Ohio State University and Argonne National Laboratory.

The research was supported by the Cornell Center for Materials Research, a National Science Foundation-funded Materials Research and Engineering Center (MRSEC), and corresponding MRSECs at Penn State and Ohio State.


TOPICS: Science
KEYWORDS: stringtheory

1 posted on 08/18/2010 12:33:44 PM PDT by decimon
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To: SunkenCiv

Ferrocious first-principles ping.


2 posted on 08/18/2010 12:34:38 PM PDT by decimon
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To: decimon

We used something like this as variable fine tuning capacitors.


3 posted on 08/18/2010 12:41:00 PM PDT by HuntsvilleTxVeteran ((B.?) Hussein (Obama?Soetoro?Dunham?) Change America Will Die From.)
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To: decimon

LOL. HOW MUCH did this thin film basic research cost? How many chilrun could have been fed instead of discovering “that thin films of europium titanate become both ferroelectric (electrically polarized) and ferromagnetic (exhibiting a permanent magnetic field) when stretched across a substrate of dysprosium scandate, another type of oxide.

Actually it’s kinda cool.


4 posted on 08/18/2010 12:41:14 PM PDT by Blueflag (Res ipsa loquitur)
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To: decimon
A material with this magical combination

I know I'm being picky, but the above is a bad use of language. There was another thread here last week, talking about a different scientific advancement which (IIRC) said that something happened "through a magical process".

When our science writers "explain" science by saying "it's magic", we have a problem.

5 posted on 08/18/2010 12:52:29 PM PDT by ClearCase_guy
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To: decimon

Dang! This sounds like “The Magical Thajical Compound” that an old PE friend used to joke about. “Guaranteed to never break, rip, buckle or bust! The longer you wear it the thicker it gets!” Yep! That’s it, alright!

Actually, I’m a sucker for new stuff. I think it’s great. If they hurry up they may be able to actually make something out of it before Jesus comes back in the Rapture. That’s when I’m leaving.......with HIM! ;oD


6 posted on 08/18/2010 1:01:58 PM PDT by Tucker39
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To: HuntsvilleTxVeteran
We used something like this as variable fine tuning capacitors.

Yeah but what about flux capacitors?

7 posted on 08/18/2010 1:12:50 PM PDT by To Hell With Poverty (The War on Poverty is over. Poverty won. - Howie Carr)
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To: Blueflag

I wish there had been more of a discussion of applications.


8 posted on 08/18/2010 1:19:30 PM PDT by achilles2000 ("I'll agree to save the whales as long as we can deport the liberals")
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To: achilles2000

I also wanted a discussion of possible uses. I have no clue and I’m an engineer. And those are some rare elements, all of them I suspect. How much would this cost for useful electronics?


9 posted on 08/18/2010 1:25:52 PM PDT by RadiationRomeo (Step into my mind and glimpse the madness that is me)
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To: RadiationRomeo
How much would this cost for useful electronics

The thing is there is almost no way to predict what it will be useful for. When something is this new and this different from available similar materials it could be useful in ways we just aren't thinking of because in the past they were uneconomical or impossible to engineer. As for cost, that is a chicken and egg thing. If no one has a use for it then it will be expensive. If it is super useful then someone will figure out how to mass produce it.
10 posted on 08/18/2010 2:49:57 PM PDT by TalonDJ
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To: decimon; AdmSmith; bvw; callisto; ckilmer; dandelion; ganeshpuri89; gobucks; KevinDavis; ...
Thanks decimon!

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11 posted on 08/18/2010 9:11:25 PM PDT by SunkenCiv ("Fools learn from experience. I prefer to learn from the experience of others." -- Otto von Bismarck)
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