Dislocation structures of low-angle boundaries in Nb-doped SrTiO3 bicrystals
Dislocation structures of low-angle boundaries in Nb-doped SrTiO3 bicrystals
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DOI：
10.1007/s10853-006-7824-9
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发表时间：
2006-04
影响因子：
4.5
通讯作者：
S. Choi;J. Buban;M. Nishi;H. Kageyama;N. Shibata;T. Yamamoto;S. Kang;Y. Ikuhara
中科院分区：
文献类型：
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作者：
S. Choi;J. Buban;M. Nishi;H. Kageyama;N. Shibata;T. Yamamoto;S. Kang;Y. Ikuhara
用高分辨电子显微镜研究了掺Nb的SrTiO_3双晶小角度晶界的位错核结构。在1873℃下连接两个单晶，得到了相对于[001]区轴倾角分别为2°、4°、6°和8°的双晶。所有的晶界均由规则的位错阵列组成，其间距随着倾角的增大而逐渐减小。除2°倾角边界外，位错核从[010]分解为a/2[010]on(100)的两个部分。此外，还观察到了两种位错核结构：核内的锶-锶原子柱和钛-氧原子柱。此外，随着倾角从4°增加到8°，相邻核心沿边界的位置有由线形向锯齿形变化的趋势。在线性阵列的情况下，位错核结构交替出现，包括锶-锶柱或钛-氧柱。相反，在锯齿形阵列中只观察到一种核心结构。另一方面，在2°倾角边界的位错核具有另一种类型的解离，a/2[110]or2[111]部分，其中包括[001]倾斜轴上的扭转分量。
Dislocation core structures in low-angle boundaries of Nb-doped SrTiO3bicrystals were investigated by high-resolution electron microscopy. Bicrystals with tilt angles of 2°, 4°, 6° and 8° with respect to the [001] zone axis were prepared by joining two single crystals at 1873 K. All of the boundaries consisted of a regular array of dislocations whose spacing gradually decreased with an increase in tilt angle. Except for the 2° tilt-angle boundary, the dislocation cores exhibited a dissociation froma[010] into two partials ofa/2[010] on (100). Furthermore, two kinds of dislocation core structures were observed; Sr–Sr atomic columns and Ti–O atomic columns inside the cores. In addition, it was found that the positioning of adjacent cores along the boundary tended to change from a linear form to a zig-zagg shape as the tilt angle was increased from 4° to 8°. In the case of the linear array, dislocation core structures including Sr–Sr columns or Ti–O columns alternately appear. In contrast, only one core structure was observed in the zig-zagged array. On the other hand, the dislocation cores in the 2°-tilt-angle boundary had another type of dissociation witha/2[110] ora/2[111] partials, which included the twist component at a tilt axis of [001].