Growth and magnetic properties of ultrathin single crystal Fe_3O_4 film on lnAs(100)

摘要

Half-metallic magnetite Fe_3O_4 (magnetite) has attracted great attention recently for spintronics as it has high polarization at the Fermi level and relatively high electronic conductivity at room temperature, which is believed to be one of the most promising materials for spintronic applications [1, 2]. By using O_2-assisted molecular beam epitaxy (MBE) system, epitaxial growth of Fe_3O_4 films on different substrate has made it possible to study the properties of the single crystalline magnetite film [3-5]. For ultrathin magnetic films, the influence of surface or interface becomes important. The magnetic properties, especially magnetic anisotropy, which plays an important role in making spintronics devices [6, 7], may change in thin films, and it may also depend on different growth techniques and the thickness of the films. We have recently succeeded to grow Fe_3O_4 thin film on GaAs and studied its magnetic properties [8, 9]. An in-plane uniaxial can be seen from the ultrathin Fe_3O_4 film on GaAs(100), where the easy axis is along GaAs[011]. InAs, one of the narrow gap semiconductors, has higher low-field mobility than that of the GaAs, which makes it an excellent candidate for high speed field effect transistors. In this paper, we report the epitaxial growth and the magnetic properties of different thickness of ultrathin Fe_3O_4 film on InAs(100).