MAGNETIC COLLAPSE IN TRANSITION-METAL OXIDES AT HIGH-PRESSURE - IMPLICATIONS FOR THE EARTH

Magnetic collapse in transition metal ions is predicted from first-pri nciples computations at pressures reached in the Earth's lower mantle and core. Magnetic collapse would lead to marked changes in geophysica lly important properties, such as elasticity and conductivity, and als o to different geochemical behavior, such as element partitioning, tha n estimated by extrapolating low-pressure data, and thus change the un derstanding of Earth's structure and evolution, Magnetic collapse resu lts from band widening rather than from changes in crystal field split ting under pressure. Seismic anomalies in the outer core and the lower most mantle may be due to magnetic collapse of ferrous iron, dissolved in iron liquid in the outer core, and in solution in magnesiowustite in the lowermost mantle.