Giant Tunneling Magnetoresistance in Mn‐ and V‐Intercalated Graphene/ <i>h</i> ‐BN Based van der Waals Magnetic Tunnel Junctions

Abstract Atomic intercalation offers a powerful route for engineering 2D materials by precisely tuning interlayer electronic coupling and spin configurations. Here, a strategy is proposed for the construction of fully 2D magnetic tunnel junctions (MTJs) based on transition metal‐intercalated graphene electrodes with h ‐BN barrier layer. First‐principles calculations reveal that intercalation not only stabilizes uniform atomic dispersion via steric hindrance but also induces spin polarization in graphene, which in turn stabilizes the ferromagnetic ground state of the intercalated atoms. Manganese‐ and vanadium‐intercalated systems (Mn‐Gr and V‐Gr) exhibit exceptional spintronic performance, with tunneling magnetoresistance (TMR) showing a pronounced odd‐even oscillation as a function of barrier thickness. A giant TMR of 4.35 × 10 8 % is achieved in the Mn‐Gr system with a monolayer barrier h ‐BN ( n = 1), while V‐Gr reaches a maximum TMR of 1.86 × 10 5 % for a trilayer barrier ( n = 3). Moreover, biaxial strain further enhances the TMR to 10 9 % and 10 7 % in Mn‐Gr and V‐Gr systems, respectively. The devices also exhibit perfect spin filtering and pronounced negative differential resistance, offering new opportunities for high‐performance spintronic and memory applications based on 2D van der Waals heterostructures. Additional GGA+ U calculations ( U = 4 eV, J = 1 eV for Mn and V) confirm that strong on‐site Coulomb interactions further increase the equilibrium TMR values (up to 8.61 × 10 8 % and 4.46 × 10 5 % for Mn‐ and V‐intercalated MTJs, respectively) without altering the main n ‐dependent trends or the qualitative even‐odd transport characteristics, thereby validating the robustness of the key findings.