▎ 摘　　要

We demonstrate the spin filtering effect in Co|MgO|TiOx|graphene junctions and a large negative spin polarization in graphene at room temperature. By systematically introducing Ti (TiOx) clusters to the exfoliated few-layer graphene, we confirm that the Ti (TiOx) clusters will increase the charged impurity scattering and lead to a decreased momentum scattering time and an abnormal Gaussian broadening effect. However, the spin relaxation mechanism is not significantly affected, indicating that the spin relaxation mechanism of graphene will not be affected by the atomic-scale Ti (TiOx) clusters induced charged impurity scattering. (C) 2017 Elsevier Ltd. All rights reserved.