Transport Studies of Exchange Interaction at Magnetic-Insulator/Graphene and Magnetic-Insulator/Topological-Insulator Interfaces

Spintronics, where carrier spin instead of charge serves as the state variable, is a promising candidate for post-CMOS low-voltage logic. An essential component of the spin-FET class of spintronic devices is the electrical modulation of spin. To realize this functionality, we explore the interfacial exchange interaction of quasi-2D systems in proximity to a magnetic insulator (MI). We study the magneto-transport of graphene/MI heterostructures as the model system. In this talk, we will discuss several schemes for probing the interfacial exchange. We demonstrate that the H-bar configuration exhibits strong enhancement in non-local resistance as a result of the exchange interaction. We will also present the magneto-transport results of MI multilayers on topological insulators as another platform for building low-voltage spintronic devices.