Nanoscale Stoichiometric Analysis of a High-Temperature Superconductor by Atom Probe Tomography.
Nanoscale Stoichiometric Analysis of a High-Temperature Superconductor by Atom Probe Tomography.
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通过原子探针断层扫描对高温超导体进行纳米级化学计量分析。
DOI：
10.1017/s1431927616012757
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Pedrazzini S
中科院分区：
文献类型：
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作者：
Pedrazzini S
高温超导体Y1 Ba 2Cu 3 O 7 −δ（Y-123）的功能特性与精确的化学计量和氧含量密切相关。超过每五个单元电池1个氧空位的临界值（δ>0.2，相当于与Y7.7Ba15.3Cu23O54-δ的名义氧化学计量偏差1.5at %）足以改变超导性能。在纳米尺度上的化学计量，特别是氧和其他较轻的元素，是非常难以量化的复杂的功能陶瓷，目前可用的分析技术。本研究是一个分析和优化的实验条件所需的量化的本地纳米级化学计量的单晶钇钡铜氧化物（YBCO）样品在三维原子探针层析成像（APT）。APT分析需要系统地探索各种数据采集和处理条件，以校准测量值。激光脉冲能量，离子识别，和范围宽度的选择都被发现影响成分测量。从具有优化超导性能的熔融生长晶体获得的最终组合物为Y7.9Ba10.4Cu24.4O57.2。
The functional properties of the high-temperature superconductor Y1Ba2Cu3O7−δ(Y-123) are closely correlated to the exact stoichiometry and oxygen content. Exceeding the critical value of 1 oxygen vacancy for every five unit cells (δ>0.2, which translates to a 1.5 at% deviation from the nominal oxygen stoichiometry of Y7.7Ba15.3Cu23O54−δ) is sufficient to alter the superconducting properties. Stoichiometry at the nanometer scale, particularly of oxygen and other lighter elements, is extremely difficult to quantify in complex functional ceramics by most currently available analytical techniques. The present study is an analysis and optimization of the experimental conditions required to quantify the local nanoscale stoichiometry of single crystal yttrium barium copper oxide (YBCO) samples in three dimensions by atom probe tomography (APT). APT analysis required systematic exploration of a wide range of data acquisition and processing conditions to calibrate the measurements. Laser pulse energy, ion identification, and the choice of range widths were all found to influence composition measurements. The final composition obtained from melt-grown crystals with optimized superconducting properties was Y7.9Ba10.4Cu24.4O57.2.