We report on a comprehensive investigation of the effects of strain and film thickness on the structural and magnetic properties of epitaxial thin films of the prototypal $J_{\mathrm{eff}}=1/2$ compound ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ by advanced x-ray scattering. We find that the ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ thin films can be grown fully strained up to a thickness of 108 nm. By using x-ray resonant scattering, we show that the out-of-plane magnetic correlation length is strongly dependent on the thin film thickness, but independent of the strain state of the thin films. This can be used as a finely tuned dial to adjust the out-of-plane magnetic correlation length and transform the magnetic anisotropy from two-dimensional to three-dimensional behavior by incrementing film thickness. These results provide a clearer picture for the systematic control of the magnetic degrees of freedom in epitaxial thin films of ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ and bring to light the potential for a rich playground to explore the physics of $5d$ transition-metal compounds.

中文翻译：

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通过应变和薄膜厚度的变化精确控制Sr2IrO4外延薄膜中Jeff = 12的磁性

我们报告了应变和膜厚度对原型外延薄膜的结构和磁性的影响的全面调查 ${Ĵ}_{效}=\mathrm{1个}/2$ 复合 $r_2{\mathrm{氧化铁}}_4$通过先进的X射线散射。我们发现$r_2{\mathrm{氧化铁}}_4$薄膜可以完全应变生长至108 nm的厚度。通过使用X射线共振散射，我们表明面外磁相关长度在很大程度上取决于薄膜厚度，但与薄膜的应变状态无关。可以将其用作微调刻度盘，以通过增加膜厚来调整平面外磁相关长度，并将磁各向异性从二维行为转换为二维行为。这些结果为系统控制外延薄膜的磁自由度提供了更清晰的画面。$r_2{\mathrm{氧化铁}}_4$ 并发掘了一个丰富的游乐场的潜力，可以探索 $5d$ 过渡金属化合物。