Fully Electrically Controlled van der Waals Multiferroic Tunnel Junctions

The fully electrical control of the magnetic states in magnetic tunnel junctions is highly pursued for the development of the next generation of low-power and high-density information technology. However, achieving this functionality remains a formidable challenge at present. Here we propose an effective strategy by constructing a trilayer van der Waals multiferroic structure, consisting of CrI₃-AgBiPSe₆ and Cr₂Ge₂Te₆-In₂Se₃, to achieve full-electrical control of multiferroic tunnel junctions. Within this structure, two different magnetic states of the magnetic bilayers (CrI₃/Cr₂Ge₂Te₆) can be modulated and switched in response to the polarization direction of the adjacent ferroelectric materials (AgBiPSe₆/In₂Se₃). The intriguing magnetization reversal is mainly attributed to the polarization-field-induced band structure shift and interfacial charge transfer. On this basis, we further design two multiferroic tunnel junction devices, namely, graphene/CrI₃-AgBiPSe₆/graphene and graphene/Cr₂Ge₂Te₆-In₂Se₃/graphene. In these devices, good interfacial Ohmic contacts are successfully obtained between the graphene electrode and the heterojunction, leading to an ultimate tunneling magnetoresistance of 9.3 × 10⁶%. This study not only proposes a feasible strategy and identifies a promising candidate for achieving fully electrically controlled multiferroic tunnel junctions but also provides insights for designing other advanced spintronic devices.