Enhanced multiferroic properties of Bi4Ti3-xCoxO12/La0.67Sr0.33MnO3 layered composite thin films

Abstract

In this work, Bi4Ti3-xCoxO12/La0.67Sr0.33MnO3 (BITCx/LSMO, x = 0.025, 0.05, 0.10 and 0.15) layered magnetoelectric (ME) composite thin films were successfully synthesized by chemical solution deposition, and the effect of Co2+ doping content on the microstructure, leakage, dielectric property, ferroelectricity, ferromagnetism and ME coupling performance of BITCx/LSMO composite thin films was investigated. Co2+ doping induces improved ferroelectricity and weak ferromagnetism for the BITCx phase. Especially, the single-phase BITC0.05 film exhibits a maximum ME voltage coefficient (αE) of 0.445 mV/cm·Oe at room temperature, suggesting excellent single-phase multiferroic properties. The BITC0.05/LSMO composite thin film possesses the lowest leakage current density, maximum ϵr, minimum tanδ, highest remnant polarization of 24.2 μC/cm2, lowest coercive field of 137 kV/cm and improved saturation magnetization along with a maximum aE value of 27.3 V/cm·Oe. Based on these findings, Co2+-doped Bi4Ti3O12 has excellent single-phase multiferroic properties, and the incorporation of magnetic ion-doped Bi4Ti3O12 with ferromagnetic oxides benefits the improvement of ME composite thin films.