Lattice dynamics and negative search for pyroelectricity in Sr(1-1.5x)LaxTiO3 ceramics

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Almeida, A (Author) FCUP; Chaves, MR (Author) Other; Gregora, I (Author) Other; Muga, NJ (Author) Other; Vilarinho, PM (Author) Other; Kholkin, AL (Author) Other; Costa, AM (Author) Other

Journal

Title: Ferroelectrics

Vol. 318

Pages: 147-153

ISSN: 0015-0193

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 2 Citations

Other information

Authenticus ID: P-000-5QF

DOI: 10.1080/00150190590966252

Abstract (EN): Lattice dynamics and polar properties in lanthanum doped SrTiO3 (STO) ceramics, with general formulae Sr(1-1.5x)LaxTiO3 were studied in the temperature range between 10 K and room temperature. Despite the similarities of the lowfrequency Raman spectra, for differently (x = 0.0533, 0.080 and 0.133) La-doped ceramics, and the spectra of the undoped ceramics, the TO1 polar soft mode could not be detected in those systems, which confirms the non-existence of a ferroelectric phase at low temperatures. Raman spectra analysis provides evidence for drastic effects determined by La3+ impurity in the critical temperature shift of the para-antiferrodistortive phase transition of STO, accompanied with a continuing change of the lattice dynamics by increasing lanthanum concentration. The absence of a pyroelectric current confirms the non-existence of a polar character in the low temperature range. The existence of semiconduting like behaviour at high temperatures was disclosed.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7