Influence of annealing oxygen pressure on in-plane epitaxy and twinning in (110) YBa 2 Cu 3 O 7 − δ thin films
Influence of annealing oxygen pressure on in-plane epitaxy and twinning in (110) YBa 2 Cu 3 O 7 − δ thin films
复制标题
退火氧气压力对(110)YBa 2 Cu 3 O 7 − δ薄膜面内外延和孪生的影响
DOI：
10.1103/physrevb.60.707
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Y. Segawa
中科院分区：
文献类型：
--
作者：
X. Qiu;H. Koinuma;M. Iwasaki;M. Kawasaki;Y. Segawa
退火氧分压对(110)取向面内外延和孪晶形成的影响 ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ 在 (110) 上生长的 (YBCO) 薄膜 ${\mathrm{SrTiO}}_{3}$ 脉冲激光沉积基底已经通过高分辨率 X 射线衍射进行了研究，使用四圆衍射仪的衍射空间映射。发现这些薄膜具有这样的结构，其中晶体 a 和 b 轴与基板的轴倾斜约 $0.5\ifmmode^\circ\else\text Degree\fi{}$，同时保持 (110) 平面彼此平行。原位退火氧气压力的降低会导致孪生现象的减少，最终在600毫托氧气压力下退火的薄膜中孪生现象被抑制。我们的结果表明，四方晶系向斜方晶系转变过程中孪晶的形成是由邻近基底表面在界面上施加的单轴力与源自正交晶系YBCO a轴和b轴晶格参数差异的热动力之间的竞争控制的。
The effects of annealing oxygen partial pressure on the in-plane epitaxy and twin formation in (110)-oriented ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ (YBCO) thin films grown on (110) ${\mathrm{SrTiO}}_{3}$ substrates by pulsed laser deposition have been studied by high-resolution x-ray diffraction, using diffraction-space mapping with a four-circle diffractometer. These films are found to have a structure in which the crystalline a and b axes are tilted about $0.5\ifmmode^\circ\else\textdegree\fi{}$ away from those of the substrates, while keeping the (110) planes parallel to each other. A decrease of in situ annealing oxygen pressure induces a reduction in twinning, which is finally suppressed in the film annealed at an oxygen pressure of 600 mTorr. Our results suggest that twin formation during a tetragonal-to-orthorhombic transformation is controlled by competition between the uniaxial force exerted at the interface by the vicinal substrate surface and the thermodynamic force originating from the difference in the lattice parameters for the a and b axes of orthorhombic YBCO.