Magnetic Proximity Effect and Interlayer Exchange Coupling of   Ferromagnetic/Topological Insulator/Ferromagnetic Trilayer
  Magnetic proximity effect between topological insulator (TI) and ferromagnetic insulator (FMI) is considered to have great potential in spintronics. However, a complete determination of interfacial magnetic structure has been highly challenging. We theoretically investigate the interlayer exchange coupling of two FMIs separated by a TI thin film, and show that the particular electronic states of the TI contributing to the proximity effect can be directly identified through the coupling behavior between two FMIs, together with a tunability of coupling constant. Such FMI/TI/FMI structure not only serves as a platform to clarify the magnetic structure of FMI/TI interface, but also provides insights into designing the magnetic storage devices with ultrafast response. 
Mingda Li, Wenping Cui, Jin Yu, Zuyang Dai, Zhe Wang, Ferhat Katmis,   Wanlin Guo, Jagadeesh Moodera
cond-mat.mes-hall cond-mat.mtrl-sci