Iron oxide in Earth’s interior exhibits unexpected electrical conductivity

BBC : At the extreme pressures and temperatures of Earth’s interior, iron oxide changes from insulator to conductor while still retaining its structure, according to a team at the Carnegie Institution of Washington.The researchers subjected the material to conditions found at the boundary between Earth’s two innermost layers and found that at a pressure of 690 000 atmospheres and a temperature of 1650 °C, the iron oxide metallizes without any change in structure. Moreover, their simulations show that its electrons behave differently from those of other metals. Because much of Earth’s mantle is composed of iron oxide and magnesium, the metallization of the iron oxide means it could electrically link the core and the mantle, which would affect the way the magnetic field propagates to Earth’s surface and beyond. The team’s results are to be published in Physical Review Letters.