Magneto-electric coupling at metallic surfaces

磁电耦合允许通过施加电场来影响物质的磁性状态。这种效应主要在绝缘多铁体或半导体铁磁体中观察到，而在金属中基本上被忽略了，因为电场不能深入金属。然而，在金属表面，电场既可以诱导电子状态的变化（例如d带填充），也可以诱导最顶层原子层的表面弛豫。本研究将利用扫描隧道显微镜对超薄磁性薄膜和表面金属铁磁体中的磁电耦合进行实验研究，并利用蚁群算法对其进行理论研究。特别是，在局部电场的作用下，铁磁体心立方（bcc）和反铁磁面心立方（fcc）铁之间的相变将成为重点，包括相变动力学的各个方面，以及在使用bcc铁的Fe（IIO）表面时使用这种效应作为数据存储的可能性。进一步研究了电场对磁性薄膜自旋重定向跃迁的影响。

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.