Aurivillius layer-structured multiferroic materials
2019 Copyright All rights reserved. Multiferroic materials exhibit the coexistence of ferromagnetic, ferroelectric, or ferroelastic orders. Multiferroic material with cross-coupling properties at room temperature (RT) exist rarely in nature; the new design of nanoengineered thin films with strong magneto-electric (ME) coupling is both fundamentally and practically challenging. Here we present our recent advances in the Aurivillius layered multiferroics of Bi5Ti3FeO15 (BTFO15), Bi6Ti3Fe2O18 (BTFO18), Bi7Ti3Fe3O21 (BTFO21), and Bi9Ti3Fe4O27 (BTFO27). The ME coupling of ~400mV/Oe.cm at RT in BTFO15 thin film has been observed, which is much higher than the previously reported value of 0.1mVcm-1Oe-1 and 8.28mVcm-1Oe-1 in the ceramic samples. Their microstructures show the strong intergrowth of the layer structure in this class of material. Scanning probe microscope measurement shows the magnetic domain switched together with the electric domain by an electric field. The disappearance of magnetic ordering evidenced by magnetization measurement therefore leads us to conclude that overall spin disordering with localized ordering is characteristic of this class of material during ME coupling. Our work could also point the way for research into novel multiferroic material in locally magnetic ordered systems.