Abstract:

The electrons in the nanometer scale thin films could be confined to form quantum well states (QWS), and many novel thickness-dependent oscillation of physical properties induced by QWS in non-magnetic films were discovered. Modern magnetoeletronics devices are based on metallic films with thicknesses on the nanometer scale, so it would be very important to experimentally explore how the QWS in ferromagnetic films affect the intrinsic magnetic properties in magnetic nanostructure research. In this talk, we will report the study on thickness- and temperature-dependent step-induced in-plane magnetic anisotropy of Fe films grown on vicinal Ag(1,1,10) surface utilizing magneto-optic Kerr effect. At low temperatures, below 200 K, the magnetic in-plane uniaxial anisotropy strongly oscillates as a function of Fe thickness with the period of 5.7 monolayers(ML). For the sample covered with Au, also the easy magnetization axis oscillates between perpendicular and parallel to the steps with the same period. Our results also indicate the out-of-plane magnetic anisotropy of Fe films oscillates with the Fe thickness. Such oscillation of magnetic anisotropy is attributed to the quantum well states (QWS) of the d-band electrons in Ferromagnetic Fe films, and this QWS was directly observed in Fe/Ag(001) system by the angular-resolved photoemission spectroscopy(ARPES). The lack of oscillation at RT may result from the thermal reduction of the electron mean free path.
 
 
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