Electric field controlled perpendicular exchange bias in Ta/Pt/Co/IrMn/Pt heterostructure

Perpendicular exchange bias (PEB) is an essential effect of antiferromagnetic materials. It has the advantages over the in-plane exchange bias in application of magnetic random access memory (MRAM) technology, particularly in terms of higher packing density. The influence of the strain effect on PEB of Ta/Pt/Co/Ir20Mn80/Pt multilayers deposited on the piezoelectric substrate is studied in this work. It is found that the exchange bias field (H-ex) can be regularly regulated by the strain effect introduced by the piezoelectric substrate. It indicates that the uncompensated spins at the interface of Ir20Mn80/Co can be reoriented under the strain effect, resulting in the variation of H-ex. Furthermore, we propose a MRAM device structure based on the strain-mediated PEB, which enables field-free magnetization switching driven by the pure strain. Our study demonstrates the controllability of PEB and its application in spintronics, providing a method for the development of antiferromagnetic material-based next generation MRAM.