Magnetoelectric composite films of La0.67Sr0.33MnO3 and Fe-substituted Bi4Ti3O12 fabricated by chemical solution deposition

Abstract

Magnetoelectric composite layered films of La0.67Sr0.33MnO3 (LSMO) and Fe-substituted Bi4Ti3O12 (Bi4Ti3-xFexO12, BiTFx, x = 0.05, 0.10, 0.15 and 0.20) were fabricated on a LaNiO3-buffered silicon substrate by chemical solution deposition method. The LaNiO3 layer with c-axis orientation can not only induce the oriented growth of the overlaying LSMO and BiTFx layers, but also can act as an electrode material for electric measurements. The Fe-substituted content has a significant effect on the surface morphology of BiTFx phase, and leakage, dielectric and ferroelectric properties of the BiTFx/LSMO films. The BiTF0.10/LSMO composite film exhibits an improved leakage performance, the highest dielectric constant and the best ferroelectric properties. Furthermore, an interesting finding is that a weak ferromagnetism is present in the BiTF0.10 phase. The first-principle calculations suggest that the spin-resolved total density of states for BiTF0.10 are asymmetric, which can induce spin splitting and magnetic moments. The BiTF0.10/LSMO film also exhibits excellent magnetoelectric coupling performance, and its magnetoelectric coupling response is sensitive to AC magnetic frequency. The highest magnetoelectric coupling voltage coefficient can reach up to 47.5 V/cm·Oe without the presence of DC bias magnetic field.