Control of Magnetic Anisotropy in Strained La2/3Sr1/3MnO3 Films by a BaTiO3 Overlayer in an Artificial Multiferroic System

We studied in detail the in-plane magnetic properties in heterostructures based on a ferroelectric BaTiO3 overlayer deposited on a ferromagnetic La2/3Sr1/3MnO3 film grown on pseudocubic (001)-oriented SrTiO3, (LaAlO3)0.3(Sr2TaAlO6)0.7 and LaAlO3 substrates. In this configuration, the combination of both functional perovskites constitutes an artificial multiferroic system with potential applications in spintronic devices based on the magnetoelectric effect. We have grown the La2/3Sr1/3MnO3 single layers and BaTiO3/La2/3Sr1/3MnO3 bilayers by pulsed-laser deposition technique. We analyzed the films structurally through X-ray reciprocal space maps, and high-angle annular dark field microscopy; magnetically, via thermal demagnetization curves and in-plane magnetization versus applied magnetic field loops, at room temperature. Our results indicate that the BaTiO3 layer induces an additional strain in the La2/3Sr1/3MnO3 layers close to their common interface. We observed that the presence of BaTiO3 on the surface of tensile-strained La2/3Sr1/3MnO3 films transforms the in-plane biaxial magnetic anisotropy present in the single layer towards an in-plane uniaxial magnetic anisotropy. Our experimental evidence suggests that this change in the magnetic anisotropy only occurs in tensile-strained La2/3Sr1/3MnO3 film and is favored by an additional strain on the La2/3Sr1/3MnO3 layer promoted by BaTiO3 film. These findings reveal an additional mechanism that alters the magnetic behavior of the ferromagnetic layer and, consequently, deserves future in-depth research to determine how it can modify the magnetoelectric coupling of this hybrid multiferroic system.