Abstract Compared with 3d-electron transition metal oxides (TMOs), 5d-electron TMOs, particularly iridates, have strong competition between spin-orbit coupling and on-site Coulomb repulsion due to their comparable energies. By using aberration-corrected transmission electron microscopy, we have studied at an atomic scale the Sr3Ir2O7 sample with a bilayered perovskite structure, which is synthesized under high pressure and high temperature. In addition, we have also investigated its magnetic and electrical properties. Our results show that the Sr3Ir2O7 possesses two kinds of structures: a tetragonal structure (I4/mmm) and an orthorhombic structure (Ccce) with complex magnetic and electrical properties. We observed that there are often 90° domain structures along the b axis of the orthorhombic structure of Sr3Ir2O7, which might be associated with the essence of antiferromagnetic 90° domains.

中文翻译：

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Sr3Ir2O7 的相多样性和畴结构

摘要 与 3d 电子过渡金属氧化物 (TMOs) 相比，5d 电子 TMOs，尤其是铱酸盐，由于它们的能量相当，在自旋轨道耦合和现场库仑排斥之间具有强烈的竞争。通过使用像差校正透射电子显微镜，我们在原子尺度上研究了在高压和高温下合成的具有双层钙钛矿结构的 Sr3Ir2O7 样品。此外，我们还研究了它的磁和电性能。我们的研究结果表明，Sr3Ir2O7 具有两种结构：四方结构 (I4/mmm) 和正交结构 (Ccce)，具有复杂的磁和电特性。我们观察到沿着 Sr3Ir2O7 的正交结构的 b 轴经常有 90°的畴结构，