分子吸着による表面磁性制御

抄録

Molecular adsorptions affect on the magnetism of magnetic thin films. We have observed anomalous magnetic states in gas adsorbed Fe thin films. In this report, we present the CO or NO adsorption effects on the magnetism of 2-4 ML Fe thin films on Cu(001), which are typical magnetic thin films. The Fe(2 ML)/Cu(001) film does not change its magnetic structure upon CO adsorption, whereas the CO/Fe(3 and 4 ML)/Cu(001) films turned their easy axes of magnetization to in plane. Depth resolved XMCD measurements give us detailed information on the depth profile of the magnetic structures. The surface two layers of the CO/Fe(4 ML)/Cu(001) film lose the magnetization, and only the bottom two layers keep the magnetization. NO adsorbed Fe films have the in-plane easy axes of magnetization. Moreover, the magnetization of the topmost layer of the NO/Fe/Cu(001) films aligns in the opposite direction to the other layers. Thus, the antiferromagnetism in the surface layers has appeared in the NO/Fe/Cu(001) films.