Landmark discovery has magnetic appeal for scientists

Dec 21, 2011

A fundamental problem that has puzzled generations of scientists has finally been solved after more than 70 years. An international team of scientists has discovered a subtle electronic effect in magnetite – the most magnetic of all naturally occurring minerals – causes a dramatic change to how this material conducts electricity at very low temperatures.

The discovery gives new insight into the mineral in which mankind discovered magnetism, and it may enable magnetite and similar materials to be exploited in new ways.

The research, published in Nature, was led by the University of Edinburgh in collaboration with the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, where the experiments were conducted.

The properties of magnetite have been known for more than 2000 years and gave rise to the original concepts of magnets and magnetism. The mineral has also formed the basis for decades of research into magnetic recording and information storage materials.

In 1939, Dutch scientist Evert Verwey discovered that the electrical conductivity of magnetite decreases abruptly and dramatically at low temperatures. At about 125 Kelvin, or minus 150 degrees Celsius, the metallic mineral turns into an insulator. Despite many efforts, until now the reason for this transition has been debated and remained controversial.

When the team of scientists fired an intense X-ray beam at a tiny crystal of magnetite at very low temperatures, they were able to understand the subtle rearrangement of the mineral's chemical structure. Electrons are being trapped within groups of three iron atoms where they can no longer transport an electrical current.

Dr Jon Wright of the ESRF said: "Our main challenge was to obtain a perfect crystal, which meant using one that was tiny, just half the diameter of a human hair. Then we needed to observe subtle changes in this microscopic sample as we lowered the temperature. In Europe, this is only possible at the ESRF, thanks to the extremely high energy of its synchrotron X-rays."

Professor Paul Attfield, of the University of Edinburgh, said: "We have solved a fundamental problem in understanding the original magnetic material, upon which everything we know about magnetism is built. This vital insight into how magnetite is constructed and how it behaves will help in the development of future electronic and magnetic technologies."

Explore further: Researchers demonstrate ultra low-field nuclear magnetic resonance using Earth's magnetic field

Provided by University of Edinburgh

3.9 /5 (15 votes)

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User comments : 5

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El_Nose
3 / 5 (1) Dec 21, 2011
this article said ABOLUTELY NOTHING -- what is the discovery ?????

BOOO on the author -- why is this important - how can it be exploited -- anything ??? anyone out there
rawa1
1 / 5 (4) Dec 21, 2011
You apparently didn't realize, we could use it for construction of quantum computers or as a cancer cure in the form of nanoparticles...;-)
Cave_Man
1 / 5 (2) Dec 21, 2011
Seems like we still know relatively little about magnetism, we only have theoretical force carriers for it, we can't explain why the flow of electricity in certain materials causes a magnetic field (we only know that it does not how) and we certainly don't understand what role magnetism plays in quantum mechanics. (is it associated with the strong, the weak, or some unknown nuclear force? etc etc)
Callippo
1 / 5 (2) Dec 21, 2011
At about 125 Kelvin, or minus 150 degrees Celsius, the metallic mineral turns into an insulator. Despite many efforts, until now the reason for this transition has been debated and remained controversial.
This behavior is actually well understood and it's connected with so-called Mott transition, during which the conductor becomes Mott insulator

http://en.wikiped...nsulator

The other thing is exact modeling of it with hard numbers. But the fact, we cannot compute the boiling point of water doesn't mean, we don't understand what happens there. Actually, such modeling will not enable us to understand the boiling of fluids a much better, then we already do. But it can still serve as a good salary generator for physicists involved - and this is actually what it's important in contemporary science. It has no meaning to cover it.

http://www.aether...memo.gif

thefurlong
not rated yet Dec 21, 2011
Seems like we still know relatively little about magnetism, we only have theoretical force carriers for it, we can't explain why the flow of electricity in certain materials causes a magnetic field (we only know that it does not how)


Actually, magnetism can be derived from relativity. It is a relativistic effect due to length contraction and time dilation that charges appear to undergo when they are moving relative to something else.
Here is a good explanation:
http://skepticspl...ism.html
So, no, we do understand where magnetism comes from as long as we accept the postulates of relativity as fundamental to reality.