Giant magnetoelectric effect in Pt/Co/Ta ultrathin films with perpendicular magnetic anisotropy on Pb(Mg_1/3Nb_2/3)_0.7Ti_0.3O₃ ferroelectric substrate

Perpendicular magnetic anisotropy (PMA) is important for increasing the information storage density in the perpendicular magnetic recording media, and electric-field control of PMA is drawing much attraction due to its potential to lower energy consumption. Multiferroic heterostructures, hybrid ferromagnetic and ferroelectric, enable electric-field control of magnetism via strain-mediated magnetoelectric coupling, though most studies have focused on how to control ferromagnetic films with in-plane magnetization.
Here, we deposited Pt/Co/Ta ultrathin films with PMA on PMN-PT ferroelectric substrate and investigate the effect of electric-field-induced piezostrain on its PMA. Through measuring anomalous Hall effect (AHE) under in situ electric fields, we observed a remarkable modulation of AHE curves by electric fields and achieved a giant converse magnetoelectric coefficient (approximately −2.1×10⁻⁶ s m⁻¹), which is comparable with the largest value in the multiferroic heterostructures with in-plane magnetization. Furthermore, the in situ polar Kerr image measurements with electric fields confirmed this giant magnetoelectric effect in PMN-PT/Pt/Co/Ta multiferroic heterostructure. These results pave a way to realize future energy-efficient PMA magnetoelectric and spintronic devices.