Landmark discovery has magnetic appeal for scientists

Ancient knowledge

"We have solved a fundamental problem in understanding the original magnetic material, upon which everything we know about magnetism is built," said Professor Paul Attfield of the Centre for Science at Extreme Conditions.

Magnetite's properties have been known for more than 2000 years and gave rise to the original concepts of magnets and magnetism.

The mineral has formed the basis for decades of research into magnetic recording and information storage materials.

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

Their results were published in Nature.

Unexplained behaviour

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.

X-ray experiment

The team of scientists fired an intense X-ray beam at a tiny crystal of magnetite at very low temperatures.

Their results enabled them to understand a subtle rearrangement of the mineral's chemical structure.

Electrons are trapped within groups of three iron atoms, where they can no longer transport an electrical current.

"This vital insight into how magnetite is constructed and how it behaves will help in the development of future electronic and magnetic technologies," Attfield said.

The research was funded by the Science and Technology Facilities Council, the Engineering and Physical Sciences Research Council, and the Leverhulme Trust.

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Landmark discovery has magnetic appeal for scientists