Observation of change in the oxidation state at ferromagnet/insulator interface upon thermal annealing.
Observation of change in the oxidation state at ferromagnet/insulator interface upon thermal annealing.
复制标题
观察热退火时铁磁体/绝缘体界面氧化态的变化。
DOI：
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复制
发表时间：
2001
期刊：
影响因子：
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通讯作者：
S. Parkin
中科院分区：
文献类型：
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作者：
L. Seve;W. Zhu;B. Sinković;J. Freeland;I. Coulthard;W. Antel;S. Parkin
据报道，磁隧道结（MTJ）如Co 1-xFex/Al 2 O3/Co 1-xFex的磁阻（MR）在热退火后得到改善。我们通过比较半MTJ结构（Co 84 Fe 16/Al 2 O3）退火前后的X射线吸收谱（XAS）来研究这种改进的机制。在退火之前，XAS显示存在几埃的Co和Fe氧化物，其在250摄氏度下退火1/2小时后消失。我们将退火后增强的MR归因于界面处Co和Fe氧化物的消失，这降低了传导电子的自旋极化并引起自旋翻转散射，这两者都导致MTJ的性能较差。
It is reported that the magnetoresistance (MR) of magnetic tunneling junction (MTJ) like Co1 − xFex/Al2O3/Co1 − xFex improves upon thermal annealing. We investigate the mechanism of this improvement by comparing the X-ray absorption spectra (XAS) of half-MTJ structures (Co84Fe16/Al2O3) before and after annealing. Before annealing, XAS show the presence of few angstroms of Co- and Fe-oxides, which disappeared after annealing at 250 deg C for 1/2 hour. We attribute enhanced MR upon annealing to the disappearance of Co and Fe oxides at the interface which reduce the spin-polarization of the conduction electrons and cause spin-flip scattering, both leading to inferior performance of MTJ.