Magnetic dead layer at the interface between a Co film and the topological insulator Bi2Se3

Abstract

Co films were grown on top of topological insulator Bi 2 Se 3 (111) substrate and studied using Magneto-Optic Kerr Effect (MOKE) and X-ray Magnetic Circular Dichroism (XMCD). Both MOKE and XMCD results show that there exists a ~1.2nm thick magnetic dead layer of the Co film, i.e., ~1.2nm Co film at the Co/Bi 2 Se 3 (111) interface losses its ferromagnetic order. The Co ferromagnetic order can be completely resumed by inserting a 3 nm Ag layer between the Co and Bi 2 Se 3 , indicating that the magnetic dead layer is due to the Co/Bi 2 Se 3 interfacial mixing which is supported by the Co L edge spectroscopy result.

The Recovery of a Magnetically Dead Layer on the Surface of an Anatase (Ti,Co)O2 Thin Film via an Ultrathin TiO2 Capping Layer

“…These results suggest that surface depletion possibly caused by oxidation plays a major role in reduced magnetization in (Ti,Co)O2, since the oxygen vacancies serve as an electron donor to induce the ferromagnetism [6]. In order to recover the magnetically dead layer, the capping layer is known to be effective to protect surface oxidation [14,15]. In this study, we developed a nonmagnetic ultrathin TiO2 epitaxial capping layer for an anatase (Ti,Co)O2 epitaxial thin film.…”

“…In order to recover the magnetically dead layer, the capping layer is known to be effective to protect surface oxidation [14,15]. In this study, we developed a nonmagnetic ultrathin TiO 2 epitaxial capping layer for an anatase (Ti,Co)O 2 epitaxial thin film.…”

Investigation of Magnetic Dead Layer on Iron Silicide Surfaces

“…The c(8×4) silicide effectively minimizes the MDL since it has a stable interface structure due to the high disintegration temperature. MDL on novel electric materials such as graphene [14], topological insulators [33] has not been well understood. Future works on the FM order and MDL of ultrathin Fe films on the interfaces will have important implications for both fundamental physics and the emerging spintronics technology.…”

“…With increasing the Fe coverage, the Kerr rotation linearly increases. If the entire Fe film is ferromagnetic at the higher coverage, the intersection at zero Kerr rotation should correspond to zero Fe thickness [32,33]. However this is not the case for the silicides and Si(111) templates, and the intersections show the magnetic dead layer.…”

Interface electronic structure at the topological insulator–ferrimagnetic insulator junction

“…There are two methods for breaking the TRS; one is by doping magnetic impurities (Cr, Fe and Mn) 11,14,15,18,19 , and the other is by connecting TIs to magnetic materials (such as Fe, Co and EuS) 12,[20][21][22][23] . However, with the objective of device applications, magnetic metals in contact with TIs are not appropriate because the TI surface state is short circuited by the metallic material 24 .…”