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Free keywords:
Antiferromagnetism, Buckling, Copper compounds, Crystal structure, Honeycomb structures, Magnetic properties, Neutron diffraction, Perovskite, Specific heat, Antiferromagnetic exchange, Antiferromagnetic orderings, C-space, Crystals structures, Honeycomb lattices, Neutron diffraction measurements, Space Groups, Theoretical investigations, Triple perovskite, Strontium compounds
Abstract:
Synthesis, crystal structure, and magnetic properties of a new 2:1 ordered triple perovskite Sr3CaOs2O9 are reported. The compound crystallizes in a P21/c space group and features a unique buckled honeycomb lattice of osmium. It exhibits long-range antiferromagnetic ordering with a high Néel temperature of 385 K as confirmed by susceptibility, heat capacity, and neutron diffraction measurements and is electrically insulating. This compound is also the first example of a 2:1-ordered osmate perovskite. Theoretical investigations indicate that Sr3CaOs2O9 features a sizeable antiferromagnetic exchange between the puckered planes resulting in a high TN. The magnetic properties of the known compound Sr3CaRu2O9 are elucidated in comparison. It shows antiferromagnetic order below TN ≈ 200 K. © 2022 The Authors. Published by American Chemical Society.