Acidic aqueous solution switching of magnetism in BiFeO₃/La_1-xSr_xMnO₃ heterostructures

Control of magnetism in multiferroic heterostructures using low-energy consumption is significant both in fundamental physics and for practical applications such as storage or logic devices. Through switching the ferroelectric polarization of the whole BiFeO₃ films using an acidic aqueous solution, we studied the deterministic control of exchange coupling and magnetization in BiFeO₃/La_{1 - x}Sr_xMnO₃ heterostructures. It is found that the hole concentration of La_{1 - x}Sr_xMnO₃ is closely coupled with BiFeO₃ polarization, which can be used to switch the interfacial magnetism. The polarization-determined exchange coupling for the Sr concentration of x = 0.2 is contrary to that of x = 0.33 and 0.5 due to different double exchange strengths, while for x = 0.5, the coupling effects are more sensitive to polarization. This work provides a pathway to control interfacial magnetism and multiferroicity at a large scale using green energy.