Electrical switching of spin-polarized current in multiferroic tunneling junctions

The generation and manipulation of spin-polarized current are critical for spintronic devices. In this work, we propose a mechanism to generate and switch spin-polarized current by an electric field in multiferroic tunnel junctions (MFTJs), with symmetric interface terminations in an antiparallel magnetic state. In such devices, different spin tunneling barriers are realized by the magnetoelectric coupling effect, resulting in a spin-polarized current. By reversing the electric polarization of the ferroelectric layer, the spin polarization of current is efficiently switched for the exchange of spin tunneling barriers. By first-principles quantum transport calculations, we show that a highly spin-polarized current is obtained and manipulated by the electric field in hafnia-based MFTJs based on the proposed mechanism. We also demonstrate that four resistance states are realized in Co/HfO2/Co junctions with asymmetric interface terminations. This work provides a promising approach for realizing the electrical control of spin current for spintronic applications.