Synthesis, structure and properties of the new layered manganese oxyselenide Sr2F2Mn2Se2O

Abstract Layered manganese oxyselenide Sr 2 F 2 Mn 2 Se 2 O was predicted from the stacking of the fluorite type block [Sr 2 F 2 ] 2+ alternating regularly with the anti-CuO 2 -type Mn 2 O square planar layer and successfully synthesized using solid state reaction under vacuum. The compound crystallizes in the layered tetragonal structure with I4/mmm space group and shows a semiconducting behavior. The large discrepancy between activation energy for conductivity, E ρ = 205 meV, and thermopower, E S = 41.7 meV, indicates its polaronic transport type. The compound has strong frustrated magnetic correlation, which gives rise to low-dimensional short-range ordering at high temperature with a small-angle canted antiferromagnetic (AFM) spin lattice. Furthermore, a short-range to long-range AFM phase transition is observed at about 141 K, in accord with the small heat capacity anomaly.