Multilevel nonvolatile regulation of magnetism by electric field in amorphous hard magnetic SmCo/PMN-PT(011) heterostructure

Abstract

Multilevel nonvolatile regulation (MNR) is demonstrated in a heterostructure composed of an amorphous hard magnetic SmCo thin film and a (011)-oriented ferroelectric 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) substrate. Two alternative ways of obtaining MNR are employed: the quasi-unipolar method and the quasi-minor-loop method, both of which utilize the transition from the rhombohedral (R) to monoclinic (MB) and then to orthorhombic (O) phase in a PMN-PT substrate. The mechanism is distinct from the conventional unipolar method inducing MNR, which mainly makes use of switching the ferroelectric domain in the R phase. The introduction of these two methods provides different ideas for achieving MNR in ferromagnetic/PMN-PT heterostructures. The observed MNR in an amorphous SmCo/(011) PMN-PT heterostructure demonstrates the potential applicability of hard magnetic materials for multifunctional information storage and spintronic devices.