This study aims to investigate the properties of the metastable hexagonal barium titanate and its corresponding phase evolution with annealing treatment. Specifically, the metastable hexagonal (h) phase, its defect structure, and the tetragonal (t) one were investigated from both the first-principles computational and the experimental perspectives. The powders prepared using self-propagating high-temperature synthesis were consolidated by spark plasma sintering (SPS) under vacuum conditions. The ceramics were subjected to an annealing treatment at 800 and 1200℃ to restore the oxygen stoichiometry and initiate phase transformation. The unannealed sample had about 80 wt% of the h-BaTiO₃ phase and 8.4% oxygen defect concentration. Our first-principles calculations showed that oxygen vacancy induced spin-polarized solution with half-metallic behavior.

本研究旨在研究亚稳态六方钛酸钡的性质及其在退火处理下的相应相演变。具体而言，从第一性原理计算和实验角度研究了亚稳态六方 (h) 相、其缺陷结构和四方 (t) 相。使用自蔓延高温合成制备的粉末在真空条件下通过放电等离子烧结 (SPS) 进行固结。陶瓷在 800 和 1200 ℃下进行退火处理以恢复氧的化学计量并引发相变。未退火样品含有约 80 wt% 的 h-BaTiO ₃相和 8.4% 的氧缺陷浓度。我们的第一性原理计算表明，氧空位诱导具有半金属行为的自旋极化溶液。