Coexistence of relaxor ferroelectricity and magnetism in multi-element substituted Aurivillius phases Pb1-2xBi1.5+2xNd0.5Nb2-xMnxO9

Abstract

We synthesized the novel double-layer Aurivillius phases Pb1-2xBi1.5+2xNd0.5Nb2-xMnxO9 using the fluxes-salt approach and systematically studied its crystal structure, morphology, dielectric, ferroelectric, magnetic and optical properties. The single-phase samples for x = 0, 0.1, and 0.3 were identified by X-ray diffraction (XRD). The refinement results demonstrated that all samples adopt an A21am orthorhombic structure and the cell volume becomes smaller with increasing x values. The perovskite B-site is occupied by Nb5+/Mn3+ ions, suggesting the local distributions of Mn3+ ions as Mn–O–Mn and Mn–O–Nb bonds based on the splitting of IR spectra. The grain morphology was observed as an anisotropic plate-like that became larger with increasing x. The broader dielectric peak with a strong frequency dependence reflected the relaxor-ferroelectric behavior and the higher Tc signifies an increased structural distortion. The non-linear fashion with open ferroelectric hysteresis loops demonstrated that ferroelectric ordering occurs at room temperature. The weak ferromagnetic ordering also existed with the introduction of Mn3+ ions. Further investigation into potential multiferroic properties in Aurivillius materials will be greatly aided by these findings.