Magneto-electric coupling at metallic surfaces

点击翻译按钮获取中文摘要

Magneto-electric coupling allows to influence the magnetic state of matter by the application of an electric field. This effect has mostly been observed in insulating multiferroics or semiconducting ferromagnets and has been largely ignored for metals, as the electric field is incapable to penetrate deeply into metals. On metallic surfaces, however, the electric field can both induce a change of the electronic state (e.g. d-band filling) and of the surface relaxation of the topmost atomic layer. In this proposal, the magneto-electric coupling in ultrathin magnetic films and the surface metallic ferromagnets will be studied experimentally by scanning tunneling microscopy and theoretically by ab inito methods. In particular, the phase transition between ferromagnetic body centred cubic (bcc) and antiferromagnetic face centred cubic (fcc) iron by the application of local electric fields will be in the focus, including aspects of the transition kinetics and the possibility to use this effect as for data storage when using the Fe(IIO) surface of bcc iron. Further, the effect of electric fields on thin magnetic films near a spin reorientation transition will be studied.