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    • Keywords


      Bismuth-layered structure ferroelectric (BLSF); dielectric relaxation; spontaneous polarization; defect mechanism; stretched exponential parameter ($\beta$).

    • Abstract


      Sm$_x$Bi$_{3−x}$TiNbO$_9$ (SBTN) with $x = 0$, 0.2, 0.4, 0.6, 0.8 and 1.0, a novel type of ceramic was prepared by a conventional solid-state reaction method. X-ray diffraction patterns confirm the formation of a single-phase, and lattice parameters were calculated based on the parent compound Bi$_3$TiNbO$_9$ (BTN). Well-defined grains were seen in the scanningelectron microscopy pictures. A kink observed near 400$^{\circ}$C for all the samples in the dielectric plot as well as in the stretched exponential parameter ($\beta$) vs. temperature plot reveals the dielectric relaxation of the samples. The tolerance factor ($t$) was found to increase with increase in the size of the A-site (Bi-site) modified ion (Sm). Impedance and modulus spectroscopicstudies were conducted to understand the plausible reason for the dielectric relaxation. The relaxation was found to be well-fit with Arrhenius equation. SBTN samples showed lower dielectric loss compared to BTN. The remnant polarization, obtained from experimental, was found to be less than that of theoretically calculated polarization, using Shimakawa’s formula. The proposed defect mechanism was interpreted using FTIR and Raman spectroscopic studies.

    • Author Affiliations



      1. Material Research Laboratory, Department of Physics, Osmania University, Hyderabad 500007, India
    • Dates

  • Bulletin of Materials Science | News

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      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
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