authors |
Almeida, A; Chaves, MR; Gregora, I; Muga, NJ; Vilarinho, PM; Kholkin, AL; Costa, AM |
nationality |
International |
journal |
FERROELECTRICS |
author keywords |
quantum paraelectricity; Raman spectra; pyroelectric current; relaxors |
keywords |
STRONTIUM-TITANATE; PHASE-TRANSITION; SRTIO3 |
abstract |
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. |
publisher |
TAYLOR & FRANCIS LTD |
issn |
0015-0193 |
year published |
2005 |
volume |
318 |
beginning page |
147 |
ending page |
153 |
digital object identifier (doi) |
10.1080/00150190590966252 |
web of science category |
Materials Science, Multidisciplinary; Physics, Condensed Matter |
subject category |
Materials Science; Physics |
unique article identifier |
WOS:000230962300021
|