Verwey-Type Charge Ordering and Site-Selective Mott Transition in FeO under Pressure.

The metal-insulator transition driven by electronic correlations is one of the most fundamental concepts in condensed matter. In mixed-valence compounds, this transition is often accompanied by charge ordering (CO), resulting in the emergence of complex phases and unusual behaviors. The famous example is the archetypal mixed-valence mineral magnetite, FeO, exhibiting a complex charge-ordering below the Verwey transition, whose nature has been a subject of long-time debates.

Anomalous compression and new high-pressure phases of vanadium sesquioxide, V2O3.

We report results of a powder x-ray diffraction (XRD) study of vanadium sesquioxide, V2O3, under pressurization in a neon pressure-transmitting medium up to 57 GPa. We have established a bulk modulus value for corundum-type V2O3 of B0 = 150 GPa at B' = 4. This bulk modulus value is the lowest among those known for the corundum-type-structured oxides, e.

Structure induced Yb valence changes in the solid solution Yb(x)Ca(1-x)C2.

The solid solution Yb(x)Ca(1-x)C2 (0 ≤ x ≤ 1) was synthesized by reaction of the elements at 1323 K. The crystal structures within this solid solution, as elucidated from synchrotron powder diffraction data, depend on x and exhibit some interesting features that point to a structure dependent valence state of Yb. Compounds with x ≥ 0.

Mixed LiCo(0.6)M(0.4)PO(4) (M = Mn, Fe, Ni) phosphates: cycling mechanism and thermal stability.

The electrochemical delithiation of LiCo(0.6)M(0.4)PO(4) phosphates (M = Mn, Fe, Ni) was studied by in situ synchrotron diffraction.