Raman spectroscopy and pyroelectric studies of SrTiO3 ceramics doped with different concentrations of bismuth

• Type: Article in International Scientific Journal
• Date: 2003

Authors

Almeida, A (Author) FCUP; Teles, P (Author) Other; Chaves, MR (Author) FCUP; Vilarinho, PM (Author) Other; Baptista, JL (Author) Other

Journal

Title: Ferroelectrics

Vol. 294

Pages: 49-59

ISSN: 0015-0193

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 11 Citations

Scopus - 7 Citations

Other information

Authenticus ID: P-000-JN5

DOI: 10.1080/00150190390238603

Abstract (EN): Raman spectra and pyroelectric studies in bismuth doped SrTiO3 ceramics, with general formulae Sr(1-1.5x)BixTiO3 , were undertaken. For x=0.0053, the low frequency Raman spectra exhibit striking similarities with the spectra of the undoped ceramics also revealing the existence of a polar soft-mode TO1 , that obeys the classical Cochran softening law. The sample with x=0.133 presents a very different dynamics, and its Raman spectra give evidence for the inexistence of an anti-ferrodistorsive phase transition, that occurs in the undoped ceramics at 104 K. Pyroelectric measurements disclose the existence of small electrical dipoles probably due to polar grain boundaries, off-centre positions of Bi3+ and Ti4+ ions, and Sr vacancies, that strongly influence the behaviour of these systems with temperature variation. There is a strong evidence for the existence of a relaxor state in the x=0.133 ceramic at low temperatures.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11