Tetragonal BaCoO _<b>3</b> : A Co ^<b>4+</b> Ferromagnetic Mott Insulator.

ABSTRACT: We report the stabilization of the metastable body-centered tetragonal (BCT) phase of BaCoO₃ (BCT-BaCoO₃) under high-pressure (15 GPa) and high-temperature (1200 °C) conditions using a mixture precursor. This double perovskite adopts the EuTiO₃-type structure (space group I4/mcm), as confirmed by powder X-ray diffraction and high-resolution STEM. X-ray photoelectron spectroscopy indicates a predominant Co⁴⁺ oxidation state without detectable oxygen vacancies. Magnetization and heat capacity measurements reveal ferromagnetic ordering at T _C ∼ 107 K, attributable to the BCT-BaCoO₃ phase. Above this temperature, the mixed-phase sample exhibits Curie-Weiss paramagnetism, a low-spin to high-spin crossover upo

SUBMITTER: Xu M 

PROVIDER: S-EPMC12598853 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature