An international team of researchers has discovered a subtle electronic effect in magnetite, the most magnetic of all naturally occurring minerals. The effect causes a dramatic change to how this material conducts electricity at very low temperatures. The discovery gives new insight into the mineral in which magnetism was discovered, and it may enable magnetite and similar materials to be exploited in new ways.
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.
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.
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 story is reprinted from material from the University of Edinburgh, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.