Electrospun barium titanate/cobalt ferrite composite fibers with improved magnetoelectric performance

Abstract

In this study, we use a versatile sol–gel based electrospinning technique to fabricate nanostructured barium titanate (BaTiO₃)/cobalt ferrite (CoFe₂O₄) composite fibers and analyze their magnetoelectric response. Scanning and transmission electron microscopy images indicate that the obtained fibers are composed of fine grains which are self-assembled and arranged. X-ray diffraction (XRD) studies of the composite fibers revealed the presence of perovskite and spinel structures corresponding to BaTiO₃ and CoFe₂O₄ phases, respectively. The magnetic hysteresis loops of the resultant fibers showed that the fibers were ferromagnetic with magnetic coercivity of 650 Oe and saturation magnetization of 31 emu g⁻¹. Moreover, the magnetoelectric coefficient developed on the surface of the fibers was measured as a function of the applied external DC magnetic field. A maximum magnetoelectric coefficient of 13.3 mV cm⁻¹ Oe⁻¹ was determined for the composite fibers, which is much higher than the commonly reported values for bulk or thin film counterparts. The large magnetoelectric coefficient of the composite fibers was attributed to the nano-sized grains and their arrangement within the fibrous geometry. The intimate contact and the large interfacial area presented by the nanostructures ensured that the composites displayed strong magnetoelectric behavior. Such composite fibers show tremendous potential for magnetic field sensor applications and for magnetoelectric devices.