X-ray emission spectroscopy with a laser-heated diamond anvil cell: a new experimental probe of the spin state of iron in the Earth's interior

X-ray emission spectroscopy and X-ray diffraction have been used in conjunction with the double-sided laser-heated diamond cell technique for studying local electronic spin states of ferrous iron in magnesiowüstite-(Mg_0.75,Fe_0.25)O and its crystal structure under high pressures and temperatures in situ. The new method can be used to study 3d transition metals in oxides and silicates under conditions relevant to deep-Earth and planetary interiors.