Magnetic proximity in a van der Waals heterostructure of magnetic insulator and graphene

Abstract

Engineering 2D material heterostructures by combining the best of different materials in one ultimate unit can offer a plethora of opportunities in condensed matter physics. Here, in the van der Waals heterostructures of the ferromagnetic insulator Cr2Ge2Te6 and graphene, our observations indicate an out-of-plane proximity-induced ferromagnetic exchange interaction in graphene. The perpendicular magnetic anisotropy of Cr2Ge2Te6 results in significant modification of the spin transport and precession in graphene, which can be ascribed to the proximity-induced exchange interaction. Furthermore, the observation of a larger lifetime for perpendicular spins in comparison to the in-plane counterpart suggests the creation of a proximity-induced anisotropic spin texture in graphene. Our experimental results and density functional theory calculations open up opportunities for the realization of proximity-induced magnetic interactions and spin filters in 2D material heterostructures and can form the basic building blocks for future spintronic and topological quantum devices. ; Authors from Chalmers, ICN2, and University of Regensburg acknowledge funding from the European Union's Horizon 2020 research and innovation programme under Grant agreement no. 785219 (Graphene Flagship Core 2). The authors at Chalmers acknowledge financial support from EU FlagEra project (from Swedish Research Council VR No. 2015-06813), Swedish Research Council VR project Grants (No. 2016-03658), Graphene center and the AoA Nano program at Chalmers University of Technology. We acknowledge Dr Ron Jansen for useful discussions about proximity-induced exchange and stray Hall effects in the heterostructures. We acknowledge help from Bing Zhao in our group and staff at Nanofabrication laboratory and Quantum device laboratory for useful discussions and help in fabrication and measurements of devices. ICN2 is funded by the CERCA Programme/Generalitat de Catalunya and is supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706). M. Vila acknowledges funding from 'La Caixa' Foundation. ; Peer reviewed