The converse piezoelectric effect on electron tunnelling across a junction with a ferroelectric-ferromagnetic composite barrier

A theoretical investigation of the converse piezoelectric effect on electron tunnelling across a tunnel junction with a ferroelectric-ferromagnetic composite barrier is proposed. Transfer matrix calculations show that the spin filtering and tunnelling magnetoresistance may be enhanced or reduced due to the presence of converse piezoelectricity in the ferroelectric barrier, depending on the orientation of the electrical polarization in the barrier relative to the applied field. In addition, the tunnelling electroresistance is found to be significantly changed, not only in magnitude but also in sign. The investigation offers a new route towards controllable spin transport.