Unveiling the ambient-condition structure of Sr<sub>2</sub>FeIrO<sub>6</sub>: a triclinic phase through synchrotron-based X-ray techniques and high pressure.

Abstract

Double perovskites with the formula A₂BB'O₆, such as Sr₂FeIrO₆, are being explored as unique platforms for unveiling diverse structural, electronic and magnetic properties. Inclusion of 3d and 5d transition metals in the B and B' sites, as in Sr₂FeIrO₆, enables the study of electron correlation and spin-orbit coupling effects to tailor promising properties. The structure of Sr₂FeIrO₆ under ambient conditions has been widely debated, with theoretical and experimental studies suggesting several potential structures. This uncertainty complicates the understanding of its magnetic and electronic behaviours. High-pressure X-ray diffraction measurements, complemented by high-resolution powder X-ray diffraction studies under ambient conditions, have provided a definitive structural characterization of Sr₂FeIrO₆, crucial for interpreting its properties and guiding future research.