Electrically controllable spin filtering and switching in multiferroic tunneling junctions

We present a theoretical investigation of an electrically controllable spin filter based on multiferroic tunneling junction. This spin filter combines the exchange splitting of ferromagnets and asymmetry in energy potential due to the screening of ferroelectric polarization charges at electrodes. Transfer matrix calculations show an enhanced spin filtering efficiency, depending on the magnitude and orientation of ferroelectric polarization. A transition from a positive tunneling magnetoresistance to a negative one is also found. Furthermore, an electric controllable switching between multiple resistive states via magnetoelectric coupling is also described; this will open a different logic programing in future spintronics.