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arXiv 1912.03385cond-mat.mtrl-sci
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飞秒脉冲X射线辐照损伤钙钛矿复合氧化物外延异质结构的非热注量阈值

Non-thermal fluence threshold for femtosecond pulsed x-ray radiation damage in perovskite complex oxide epitaxial heterostructures

Hyeon Jun Lee, Youngjun Ahn, Samuel D. Marks, Eric C. Landahl, Jun Young Lee, Tae Yeon Kim, Sanjith Unithrattil, Ji Young Jo, Sae Hwan Chun, Sunam Kim, Sang-Yeo… 展开作者

Hyeon Jun Lee, Youngjun Ahn, Samuel D. Marks, Eric C. Landahl, Jun Young Lee, Tae Yeon Kim, Sanjith Unithrattil, Ji Young Jo, Sae Hwan Chun, Sunam Kim, Sang-Yeon Park, Intae Eom, Carolina Adamo, Darrell G. Schlom, Haidan Wen, Paul G. Evans

摘要:

当脉冲能量密度超过阈值时,来自自由电子激光的强硬X射线脉冲在钙钛矿氧化物外延异质结构中引起不可逆的结构损伤。使用一系列脉冲测量的来自SrTiO $_{3}$衬底上的25-nm厚外延BiFeO $_{3}$层的X射线衍射强度在9.7 keV光子能量下以2.7 × 10 - 6 $^{6}$光子$μ$ m $^{-2}$的每脉冲通量突然降低,但是对于1.3 × 10 - 15 $^{6}$光子$μ$ m $^{-2}$或更小保持恒定。该损伤导致焦斑区域内的BiFeO $_{3}$薄膜的破坏以及通过每个脉冲去除几十纳米的材料形成穿透到STO衬底中的深腔。损伤阈值发生在不足以将吸收体积加热到熔点的注量处。烧蚀样品的形态与断裂而不是熔化一致。总之,这些结果表明,通过与吸收体积的超快电离一致的非热过程发生的损伤。

英文摘要:

Intense hard x-ray pulses from a free-electron laser induce irreversible structural damage in a perovskite oxide epitaxial heterostructure when pulse fluences exceed a threshold value. The intensity of x-ray diffraction from a 25-nm thick epitaxial BiFeO$_{3}$ layer on a SrTiO$_{3}$ substrate measured using a series of pulses decreases abruptly with a per-pulse fluence of 2.7 x 10$^{6}$ photons $μ$m$^{-2}$ at 9.7 keV photon energy, but remains constant for 1.3 x 10$^{6}$ photons $μ$m$^{-2}$ or less. The damage resulted in the destruction of the BiFeO$_{3}$ thin film within the focal spot area and the formation of a deep cavity penetrating into the STO substrate via the removal of tens of nanometers of material per pulse. The damage threshold occurs at a fluence that is insufficient to heat the absorption volume to the melting point. The morphology of the ablated sample is consistent with fracture rather than melting. Together these results indicate that the damage occurs via a non-thermal process consistent with ultrafast ionization of the absorption volume.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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