Structural and multiferroic properties in double-layer Aurivillius phase Pb0.4Bi2.1La0.5Nb1.7Mn0.3O9 prepared by molten salt methodWendari, T. P., Arief, S., Mufti, N., Insani, A., Baas, J., Blake, G. R. & Zulhadjri, N. V., 15-Apr-2020, In : Journal of Alloys and Compounds. 820, 6 p., 153145.
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A single-phase sample of the Aurivillius compound Pb0.4Bi2.La0.5Nb1.7Mn0.3O9 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 A2(1)am 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 mu C/cm(2) 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 (M-r) 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.La0.5Nb1.7Mn0.3O9 exhibits coexisting ferroelectric and ferromagnetic properties. (C) 2019 Elsevier B.V. All rights reserved.
|Number of pages||6|
|Journal||Journal of Alloys and Compounds|
|Publication status||Published - 15-Apr-2020|
- Double-layer Aurivillius phase, Molten salt method, Cation disorder, Multiferroic, Relaxor-ferroelectric behavior, Ferromagnetic interactions, ELECTRICAL-PROPERTIES, CATION DISORDER