Suppression of ferroelectric phase-transition in niobates via solid solution formation

Author(s)

Lanfredi, S. ^[1] ; Praxedes, F. R. ^[1] ; Ivashita, F. F. ^[2] ; Paesano Jr, A. ; Nobre, M. A. L. ^[3]

Affiliation

^[1] Sao Paulo State Univ Unesp, Dept Chem & Biochem, Sch Technol & Sci, R Roberto Simonsen 305, BR-19060900 Presidente Prudente, SP - Brazil

^[2] Univ Estadual Maringa, Dept Phys, Av Colombo, 5790 Zona 7, BR-87020900 Maringa, Parana - Brazil

^[3] Sao Paulo State Univ Unesp, Dept Phys, Sch Technol & Sci, R Roberto Simonsen 305, BR-19060900 Presidente Prudente, SP - Brazil

• Document type: Journal article
• Source: Materials Letters; v. 254, p. 85-88, NOV 1 2019.
• Web of Science Citations: 0

Abstract

Suppression of the phase-transition type ferro-paraelectric from doping of KSr2Nb5O15 host-structure was investigated by set of techniques X-ray diffraction, Mossbauer spectroscopy and Dielectric spectroscopy at high temperature. High crystalline and single phase iron-doped niobate ceramic with Tetragonal Tungsten Bronze TTB-type structure, stoichiometry KSr2(FeNb4) O15-delta, was prepared by conventional technique using high energy milling. Both techniques Rietveld Method and Mossbauer spectroscopy showed that Fe3+ cations occupy two different octahedral sites in the TTB structure on the niobium octahedral sites, termed as Nb(1) and Nb(2). At room temperature, the dielectric permittivity value of the KSr2(FeNb4) O15-delta is two times higher than the permittivity values of the KSr2Nb5O15. The suppression with extinction of ferro-para phase-transition occurs as function of break-down of polar characteristic. New non-polar space group development stemming from solid solution formation is discussed. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 07/03510-9 - Structural characterization of nanopowders of semiconductor ferroelectric oxides
• Grantee: Silvania Lanfredi
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/11189-0 - Catalytic performance as a function of nanostructuring of new oxides catalysts from the spray pyrolysis method
• Grantee: Silvania Lanfredi
• Support Opportunities: Regular Research Grants