Methods of producing and controlling tunneling electroresistance and tunneling magnetoresistance in a multiferroic tunnel junction

Abstract

The present invention relates to magnetic random access memory (MRAM) storage devices based on multiferroic tunnel junctions in which ferroelectric polarization is used to control and manipulate the memory state. Invention methods include: (1) method of producing tunneling electroresistance (TER) effect in multiferroic tunnel junction (MFTJ) at finite bias; (2) method of controlling the TER effect in an MFTJ at infinite bias via the switching of the relative orientation of the ferromagnetic leads; (3) method of producing monotonous bias dependence of the tunneling magnetoresistance (TMR) in a MFTJ; (4) method of controlling the size and direction of the parallel spin transfer torque (STT) component and the perpendicular STT component across the MFTJ; (5) method of producing a monotonous bias dependence of the perpendicular STT component across an MFTJ; and (6) method of controlling the size and sign of the interlayer exchange coupling in an MFTJ. The invented products are any electric-field-controlled spin transfer torque magnetoresistive memory element based on a multiferoic tunnel junction (MTFJ) with magnetic electrodes and a simple or composite ferroelectric barrier embodying any of the claimed 6 methods.