New Buckled Honeycomb Lattice Compound Sr3CaOs2O9 Exhibiting Antiferromagnetism above Room Temperature

TL;DR

This study reports the synthesis and characterization of Sr3CaOs2O9, a new buckled honeycomb lattice perovskite exhibiting antiferromagnetism above room temperature, with potential implications for magnetic materials.

Contribution

It introduces a novel 2:1 ordered osmate perovskite with a buckled honeycomb lattice and high Neel temperature, expanding the family of magnetic oxides.

Findings

Exhibits antiferromagnetic order at 385 K

First example of a 2:1 ordered osmate perovskite

Shows significant antiferromagnetic exchange between puckered planes

Abstract

Synthesis, crystal structure and magnetic properties of a new 2:1 ordered triple perovskite Sr3CaOs2O9 are reported. The compound crystallizes in P21/c space group and features a unique buckled honeycomb lattice of osmium. It exhibits long-range antiferromagnetic ordering with a high Neel 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.