Charge Ordering and Incommensurate Modulations in the Metamagnetic Layered Manganese Oxysulfide Sr₂MnO₂Cu_3.5S₃.

ABSTRACT: Sr₂MnO₂Cu_3.5S₃ contains mixed-valent Mn ions Mn^2+/3+ in axially elongated MnO₄S₂ octahedra connected via apical sulfide anions to copper-deficient antifluorite-type Cu_4-δS₃ layers where δ ∼ 0.5. Copper deficiency is charge-compensated by oxidation of Mn 3d states resulting in mixed-valency. The compound is tetragonal in P4/mmm at ambient temperatures (a = 4.016345(1) Å, c = 11.40708(5) Å). Below 190 K, superlattice reflections in diffraction data and an increase in resistivity, signal checkerboard charge-ordering of Mn²⁺ and Mn³⁺. The superstructure approximates to a √2a × √2a × 2c expansion of the room temperature cell in

SUBMITTER: Crentsil LE 

PROVIDER: S-EPMC12856914 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature