Microscopic structures of MgO barrier layers in single-crystal Fe∕MgO∕Fe magnetic tunnel junctions showing giant tunneling magnetoresistance
Microscopic structures of MgO barrier layers in single-crystal Fe∕MgO∕Fe magnetic tunnel junctions showing giant tunneling magnetoresistance
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DOI：
10.1063/1.2213953
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发表时间：
2006-06
影响因子：
4
通讯作者：
M. Mizuguchi;Yoshishige Suzuki;T. Nagahama;S. Yuasa
中科院分区：
文献类型：
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作者：
M. Mizuguchi;Yoshishige Suzuki;T. Nagahama;S. Yuasa
采用原位扫描隧道显微镜对磁隧道结中MgO（001）势垒层的微观结构进行了表征。MgO薄膜表面非常平坦，沉积后退火使其梯田更加平坦。MgO表面的这种扁平化明显地促进了电子的相干输运，这应该提高隧道磁电阻比。局部隧道光谱显示，退火后的MgO层的临界厚度在3 ~ 5ml（单层）之间，在该厚度上可以形成无针孔的连续薄膜。
The microscopic structures of MgO(001) barrier layers in magnetic tunnel junctions showing giant tunneling magnetoresistance were characterized by in situ scanning tunneling microscopy. The MgO thin films formed exceedingly flat surfaces, and their terraces were made even flatter by annealing after deposition. This flattening of MgO surfaces apparently promotes coherent transport of electrons, which should enhance the tunneling magnetoresistance ratio. Local tunneling spectroscopy revealed that an annealed MgO layer has a critical thickness between 3 and 5 ML (monolayer), and a continuous film without pinholes can be formed over the thickness.