title: Spin transition zone in Earth's lower mantle.
abstract: Mineral properties in Earth's lower mantle are affected by iron electronic states, but representative pressures and temperatures have not yet been probed. Spin states of iron in lower-mantle ferropericlase have been measured up to 95 gigapascals and 2000 kelvin with x-ray emission in a laser-heated diamond cell. A gradual spin transition of iron occurs over a pressure-temperature range extending from about 1000 kilometers in depth and 1900 kelvin to 2200 kilometers and 2300 kelvin in the lower mantle. Because low-spin ferropericlase exhibits higher density and faster sound velocities relative to the high-spin ferropericlase, the observed increase in low-spin (Mg,Fe)O at mid-lower mantle conditions would manifest seismically as a lower-mantle spin transition zone characterized by a steeper-than-normal density gradient.
authors: Lawrence Livermore National Laboratory (LLNL), 7000 East Avenue, Livermore, CA 94550, USA.
authors: Jung-Fu
authors: JF
authors: Lin
authors: György
authors: G
authors: Vankó
authors: Steven D
authors: SD
authors: Jacobsen
authors: Valentin
authors: V
authors: Iota
authors: Viktor V
authors: VV
authors: Struzhkin
authors: Vitali B
authors: VB
authors: Prakapenka
authors: Alexei
authors: A
authors: Kuznetsov
authors: Choong-Shik
authors: CS
authors: Yoo