Mizuguchi M, Suzuki Y, Nagahama T, Yuasa S
Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
J Nanosci Nanotechnol. 2007 Jan;7(1):255-8.
The surface morphology of epitaxial Fe(001)/MgO(001)/Fe(001) magnetic tunnel junctions, which show the giant tunneling magnetoresistance effect, was investigated by in situ scanning tunneling microscopy. It was observed that an epitaxial MgO barrier layer forms flat surface structures. The surface was flatter with distinct steps and terraces after annealing, which would lead to an increase of the tunneling magnetoresistance ratio. Examination of the local electronic structures of 1.05-nm-thick MgO barrier layers by scanning tunneling spectroscopy revealed no pinholes in the layers, so they would be perfect barriers in magnetic tunnel junctions.
通过原位扫描隧道显微镜研究了具有巨隧穿磁阻效应的外延Fe(001)/MgO(001)/Fe(001)磁性隧道结的表面形貌。观察到外延MgO势垒层形成了平坦的表面结构。退火后，表面更平整，有明显的台阶和平台，这将导致隧穿磁阻比增加。通过扫描隧道光谱对1.05纳米厚的MgO势垒层的局部电子结构进行检查，结果表明该层中没有针孔，因此它们在磁性隧道结中是完美的势垒。
