Ferromagnet/Two-Dimensional Semiconducting Transition-Metal Dichalcogenide Interface with Perpendicular Magnetic Anisotropy

Abstract

Ferromagnet/two-dimensional transition-metal dichalcogenide (FM/2D TMD) interfaces provide attractive opportunities to push magnetic information storage to the atomically thin limit. Existing work has focused on FMs contacted with mechanically exfoliated or chemically vapordeposition-grown TMDs, where clean interfaces cannot be guaranteed. Here, we report a reliable way to achieve contamination-free interfaces between ferromagnetic CoFeB and molecular-beam epitaxial MoSe 2 . We show a spin reorientation arising from the interface, leading to a perpendicular magnetic anisotropy (PMA), and reveal the CoFeB/2D MoSe 2 interface allowing for the PMA development in a broader CoFeB thickness-range than common systems such as CoFeB/MgO. Using X-ray magnetic circular dichroism analysis, we attribute generation of this PMA to interfacial d−d hybridization and deduce a general rule to enhance its magnitude. We also demonstrate favorable magnetic softness and considerable magnetic moment preserved at the interface and theoretically predict the interfacial band matching for spin filtering. Our work highlights the CoFeB/2D MoSe 2 interface as a promising platform for examination of TMD-based spintronic applications and might stimulate further development with other combinations of FM/2D TMD interfaces.

Van der Waals magnets: Wonder building blocks for two‐dimensional spintronics?

“…Together with favorable magnetic softness, considerable magnetic moment preserved at the interface, and theoretically predicted interfacial band matching for spin filtering, this kind of FM/2D-TMD interface provides attractive opportunities for 2D spintronic devices with atomic-level control of their interface properties. 149 A similar work of enhancing the PMA by introducing a TMD layer is reported for the multilayer of Pt/[Co/Ni] 2 /MoS 2 ( Figure 7D). 150 By inserting a sputtering MoS 2 underlayer transferred onto the substrate, the PMA and spin-orbit-torque efficiency are seen to significantly enhance, originating from the effect of modified orbital hybridization at the Pt/Co interface.…”

“…A spin re‐orientation arises from the interface, leading to a PMA, generation of which is attributed to interfacial d‐d hybridization by exploiting XMCD analysis. Together with favorable magnetic softness, considerable magnetic moment preserved at the interface, and theoretically predicted interfacial band matching for spin filtering, this kind of FM/2D‐TMD interface provides attractive opportunities for 2D spintronic devices with atomic‐level control of their interface properties . A similar work of enhancing the PMA by introducing a TMD layer is reported for the multilayer of Pt/[Co/Ni] 2 /MoS 2 (Figure D) .…”

“…B, Experimental magnetoresistance in NiFe/MoS 2 /NiFe/Co spin‐valve . C, XMCD measurement geometry and hysteresis of CoFeB/MoSe 2 interface grown on graphene/SiC substrate, evidencing PMA . D, Ni/Co multilayer grown on MoS 2 with a Pt buffer layer with enhanced uniaxial magnetic anisotropy constant perpendicular to the film plane…”

“…An MBE‐based growth strategy in response to the above issue has been demonstrated, enabling wafer‐scale TMDs with full coverage on substrate and contamination‐free FM/TMD interface. Taking advantage of this growth strategy, a clean FM/2D‐TMD interface between magnetically soft CoFeB and 2D MoSe 2 is achieved (Figure C) . A spin re‐orientation arises from the interface, leading to a PMA, generation of which is attributed to interfacial d‐d hybridization by exploiting XMCD analysis.…”

“…Taking advantage of this growth strategy, a clean FM/2D-TMD interface between magnetically soft CoFeB and 2D MoSe 2 is achieved ( Figure 7C). 149 A spin re-orientation arises from the interface, leading to a PMA, generation of which is attributed to interfacial d-d hybridization by exploiting XMCD analysis. Together with favorable magnetic softness, considerable magnetic moment preserved at the interface, and theoretically predicted interfacial band matching for spin filtering, this kind of FM/2D-TMD interface provides attractive opportunities for 2D spintronic devices with atomic-level control of their interface properties.…”