Magnetism manipulated by ferroelectric polarization and epitaxial strain in a LaSrMnO/BaTiO system.

Exploring the manipulation of magnetism in perovskite oxides is scientifically interesting and of great technical importance in next-generation magnetic memory. Dual control of magnetism in superlattices through epitaxial strain and ferroelectric polarization may induce rich physical properties. In this work, we demonstrated a strong magnetoelectric coupling that appears in an La0.75Sr0.25MnO3/BaTiO3 superlattice. Reversible transitions in ferromagnetism, ferrimagnetism and anti-ferromagnetism, with strong magnetoelectric coupling, are achieved by precisely controlling the magnitude and spin-direction of the magnetic moments of Mn. Half-metallicity is demonstrated in the MnO2 layers, accompanied by the spin polarization of the superlattice varying from 100% to 0%. We realize the coexistence of ferroelectric polarization and metallicity, i.e., "ferroelectric metal". The variation in strain and re-orientation of polarization lead to a change in interfacial Ti-O and Mn-O bond lengths, and hence a hybridization state, determining the magnetism of our system. The purpose-designed LSMO/BTO superlattice with intrinsic magnetoelectric coupling is a particularly interesting model system that can provide guidance for the development of spintronic devices.