Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada.
Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA.
Phys Rev Lett. 2014 Apr 11;112(14):147201. doi: 10.1103/PhysRevLett.112.147201. Epub 2014 Apr 7.
We report x-ray resonant magnetic scattering and resonant inelastic x-ray scattering studies of epitaxially strained Sr2IrO4 thin films. The films were grown on SrTiO3 and (LaAlO3)0.3(Sr2AlTaO6)0.7 substrates, under slight tensile and compressive strains, respectively. Although the films develop a magnetic structure reminiscent of bulk Sr2IrO4, the magnetic correlations are extremely anisotropic, with in-plane correlation lengths significantly longer than the out-of-plane correlation lengths. In addition, the compressive (tensile) strain serves to suppress (enhance) the magnetic ordering temperature TN, while raising (lowering) the energy of the zone-boundary magnon. Quantum chemical calculations show that the tuning of magnetic energy scales can be understood in terms of strain-induced changes in bond lengths.
我们报告了外延应变 Sr2IrO4 薄膜的 X 射线共振磁散射和共振非弹性 X 射线散射研究。这些薄膜分别在 SrTiO3 和（LaAlO3）0.3（Sr2AlTaO6）0.7 衬底上生长，处于轻微的拉伸和压缩应变下。尽管这些薄膜发展出一种类似于体相 Sr2IrO4 的磁性结构，但磁相关性具有极强的各向异性，面内相关长度明显长于面外相关长度。此外，压缩（拉伸）应变有助于抑制（增强）磁有序温度 TN，同时提高（降低）晶带边界磁子的能量。量子化学计算表明，磁能标度的调谐可以用应变诱导的键长变化来解释。
