采用分子束外延技术在GaAs(001)-4×6衬底上外延出Fe/MgO/Fe(001) 单晶磁性隧道结。原位的表面磁光克尔效应（SMOKE）测量表明：当外磁场沿[1-10]方向时，隧道结的SMOKE回线具有典型的双矫顽力特性。下电极Fe层的矫顽力（~200 Oe）约是上电极Fe层矫顽力（~10 Oe）的20倍。矫顽力的增强主要被归结为MgO/Fe (001)界面对下电极铁磁层的钉扎作用。自旋分辩的光电子能谱测量表明，在MgO覆盖到Fe(001)表面后，Fe(001)费密面的自旋极化率P由负值转变为正值。P符号的改变被归结为MgO/Fe (001)界面电子自旋结构的改变。
Fully epitaxial Fe/MgO/Fe(001) magnetic tunneling junctions (MTJs) were fabricated on GaAs(001)-4亊6 surface. The in-situ longitudinal magneto-optical Kerr effect (MOKE) measurements showed a typical two steps MOKE loop when the magnetic field applied along [1-10] direction. It was found that the coercivity of bottom Fe electrode (200 Oe) is about 20 times higher than that of top Fe layer. A remarkably increase of the coercivity in the bottom Fe layer was attributed to the pinning effect at MgO/Fe/GaAs(001) interfaces. Spin-resolved valence band photoemission spectroscopy measurements showed that upon MgO overlayer the spin polarization at Fermi level of bcc Fe(001) reverses the sign from negative into positive. The sign reversion of the spin polarization is ascribed to a selective modification of the electronic states mainly in minority ∆5伀 symmetry involved at the MgO/Fe(001) interface.
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