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Influence of Nb5+ ions on phase transitions and polar disorder above TC in PbZrO3 studied by Raman spectroscopy |
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| Authors: | Dariusz Kajewski Irena Jankowska-Sumara Jae-Hyeon Ko Jeong W Lee Rafa? Sitko Andrzej Majchrowski Annette Bussmann-Holder Krystian Roleder |
| Affiliation: | 1. Institute of Physics, University of Silesia, Chorzów, Poland;2. Institute of Physics, Pedagogical University, Kraków, Poland;3. Department of Physics, Hallym University, Chuncheon, Korea;4. Institute of Chemistry, University of Silesia, Katowice, Poland;5. Institute of Applied Physics, Military University of Technology, Warsaw, Poland;6. Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany |
| Abstract: | Micro-Raman light scattering experiments on PbZrO3 (PZO) single crystal doped with Nb5+ have been investigated. Special attention was paid to the paraelectric (PE) phase in which nominally forbidden first-order Raman spectra were detected at temperatures far above the phase transition TC. Complex Raman spectra were observed in the vicinity of three structural phase transitions. These results mainly from the coexistence of phases with different symmetries in a wide temperature range below TC. The Raman measurements have been compared with dielectric and optical observations and proved that polar nanoregions in a centrosymmetric lattice appear well above TC. It was shown that doping ABO3 perovskites with heterovalent ions like Nb5+ unbalances charge neutrality of the lattice and strongly extends the temperature range of polar regions. The investigations performed point out that in the PE matrix the interaction between electrons and lattice vibrations, as recently suggested for pure PZO, plays an important role. |
| Keywords: | lead zirconate niobium perovskites phase transition Raman light scattering |