Tio Putra Wendari, Syukri Arief, Nandang Mufti, Andon Insani, Jacob Baas, Graeme R. Blake, Zulhadjri
A single-phase sample of the Aurivillius compound Pb0.4Bi2.1La0.5Nb1.7Mn0.3O9 was prepared by a molten salt method using K2SO4/Na2SO4 as the flux. The crystal structure, morphology, ferroelectric, and magnetic properties were investigated. Neutron powder diffraction data confirmed a non-centrosymmetric orthorhombic crystal structure with space group A21am and Pb/Bi disorder in the bismuth oxide blocks, Bi/Pb/La disorder on the perovskite A-site, and Nb/Mn disorder on the perovskite B-site. The morphology of the sample showed anisotropic plate-like grains as probed by scanning electron microscopy. The dielectric constant exhibits a transition peak between 600 K and 640 K that depends on frequency, indicating relaxor ferroelectric behavior. Electrical polarization versus applied field loops are unsaturated, with a remnant polarization of 0.43 μC/cm2 at 40 Hz under the maximum electrical field applied of 160 kV/cm. The ferroelectricity originates from the displacement of oxygen atoms in the BO6 octahedra, resulting in a polar structural distortion. Magnetic susceptibility measurements showed the presence of mixed Mn3+ and Mn4+, resulting in short-range ferromagnetic order via double exchange interactions below 33 K. The remnant magnetization (Mr) is 0.01 emu/g at 5 K. This mixed valence of Mn cations is mainly responsible for the high electrical conductivity. Thus, Pb0.4Bi2.1La0.5Nb1.7Mn0.3O9 exhibits coexisting ferroelectric and ferromagnetic properties. © 2019 Elsevier B.V.
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Andalas, Kampus Limau Manis, Padang, 25163, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia; Center for Science and Technology of Advanced Materials, National Nuclear Energy Agency of Indonesia, Puspiptek Serpong, Tangerang Selatan, 15314, Indonesia; Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747, AG Groningen, Netherlands
