Direct imaging of the structural change generated by dielectric breakdown in MgO based magnetic tunnel junctions
Direct imaging of the structural change generated by dielectric breakdown in MgO based magnetic tunnel junctions
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氧化镁基磁隧道结中介电击穿产生的结构变化的直接成像
DOI：
10.1063/1.3001934
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
M. Seibt
中科院分区：
文献类型：
--
作者：
A. Thomas;V. Drewello;M. Schaefers;A. Weddemann;G. Reiss;G. Eilers;M. Muenzenberg;K. Thiel;M. Seibt
制备了基于氧化镁的磁性隧道结来研究隧道势垒的介电击穿。通过透射电子显微镜测量，可以直接看到击穿过程。破裂的隧道结被准备用于显微镜测量，通过聚焦离子束从结出来，以输运调查为特征。因此，可以直接比较完好和断裂的结点的输运行为和结构。与早期在氧化铝基结中的发现相比，氧化镁势垒在击穿后显示出更多的微观针孔。这可以用一个简单的模型来解释，该模型假定击穿时的电流密度与针孔形成速率之间的关系。
MgO based magnetic tunnel junctions are prepared to investigate the dielectric breakdown of the tunnel barrier. The breakdown is directly visualized by transmission electron microscopy measurements. The broken tunnel junctions are prepared for the microscopy measurements by focussed ion beam out of the junctions characterized by transport investigations. Consequently, a direct comparison of transport behavior and structure of the intact and broken junctions is obtained. Compared to earlier findings in Alumina based junctions, the MgO barrier shows much more microscopic pinholes after breakdown. This can be explained within a simple model assuming a relationship between the current density at the breakdown and the rate of pinhole formation.