Work

Polymorphism of Sr2ZnIrO6 Double Perovskite at High Pressure and Temperature

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The structural behavior of Sr 2 ZnIrO 6 double perovskite has been systematically studied under extreme conditions, both at high temperature and high pressure with synchrotron powder X-ray diffraction. At high temperatures, three structural phase transitions are detected at 473, 673, and 873 K, giving the sequence P 2 1 / n → I 2/ m → I 4/ m → Fm 3̅ m . At high pressure, a phase transition from monoclinic P 2 1 / n to tetragonal I 4/ m symmetry is observed at 7.5(1) GPa, as confirmed by ab initio calculations. The tetragonal high-pressure I 4/ m polymorph appears at both high and intermediate temperatures, highlighting a displacive transition with an estimated negative pressure dependence of the critical temperature (d T c /d p = −51 K/GPa). The bulk modulus (∼150 GPa) and the volumetric thermal expansion (∼3.4 × 10 –5 K –1 ) are determined for the low- and high-pressure phases ( P 2 1 / n and I 4/ m ).

Source: Inorganic Chemistry

DOI: 10.1021/acs.inorgchem.5c02651