• Structural, dielectric and electrical properties of CaBa4SmTi3Nb7O30 ferroelectric ceramic

    • Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/034/04/0907-0914

    • Keywords

       

      Ferroelectrics; solid-state reaction; X-ray diffraction; dielectric response; electrical properties.

    • Abstract

       

      The polycrystalline sample of CaBa4SmTi3Nb7O30, a member of tungsten bronze family, was prepared by solid-state reaction method. X-ray diffraction analysis shows the formation of single-phase compound with an orthorhombic structure at room temperature. Scanning electron micrograph of the material shows uniform distribution of grains. Detailed studies of dielectric properties of the compound as a function of temperature at different frequencies suggest that the compound has a dielectric anomaly of ferroelectric to paraelectric type at 198°C, and exhibits non-relaxor kind of diffuse phase transition. The ferroelectric nature of the compound has been confirmed by recording polarization–electric field hysteresis loop. Piezoelectric and pyroelectric studies of the compound have been discussed in this paper. Electrical properties of the material have been analyzed using complex impedance technique. The Nyquist plots manifest the contribution of grain boundaries (at higher temperature), in addition to granular contribution (at all temperatures) to the overall impedance. The temperature dependence of dc conductivity suggests that the compound has negative temperature coefficient of resistance (NTCR) behaviour. The frequency dependence of ac conductivity is found to obey Jonscher’s universal power law. The observed properties have been compared with calcium free Ba5SmTi3Nb7O30 compound.

    • Author Affiliations

       

      Prasun Ganguly1 A K Jha1

      1. Thin Film and Materials Science Laboratory, Department of Applied Physics, Delhi Technological University (Formerly Delhi College of Engineering), Bawana Road, Delhi 110 042, India
    • Dates

       

© 2017-2019 Indian Academy of Sciences, Bengaluru.