Electronic Transitions in Perovskite: Possible Nonconvecting Layers in the Lower Mantle
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- 16 July 2004
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 305 (5682) , 383-386
- https://doi.org/10.1126/science.1098840
Abstract
We measured the spin state of iron in magnesium silicate perovskite (Mg 0.9 ,Fe 0.1 )SiO 3 at high pressure and found two electronic transitions occurring at 70 gigapascals and at 120 gigapascals, corresponding to partial and full electron pairing in iron, respectively. The proportion of iron in the low spin state thus grows with depth, increasing the transparency of the mantle in the infrared region, with a maximum at pressures consistent with the D″ layer above the core-mantle boundary. The resulting increase in radiative thermal conductivity suggests the existence of nonconvecting layers in the lowermost mantle.Keywords
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