%0 Journal Article %1 WOS:000181640000003 %A Maczka, M %A Souza, AG %A Freire, PTC %A Mendes, J %A Kojima, S %A Hanuza, J %A Majchrowski, A %C BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND %D 2003 %I JOHN WILEY & SONS LTD %J JOURNAL OF RAMAN SPECTROSCOPY %K bronze} ferroelectrics; hexagonal phase spectra; transitions; tungsten {Raman %N 3 %P 199-204 %R 10.1002/jrs.957 %T Pressure- and temperature-dependent Raman studies of KNbW2O9 hexagonal tungsten bronze %V 34 %X Pressure- and temperature-dependent Raman studies were performed on KNbW2O9 ferroelectric hexagonal tungsten bronze single crystal. The results suggest that some structural changes, possibly phase transitions, connected with tilting of the WO6 octahedra occur in this material at around 290-350 K and 1.0-1.4 GPa. No changes in the spectra could be observed at the 523 and 543-553 K phase transitions. The data indicate that these phase transitions lead to only weak changes in the vibrational properties of KNbW2O9, which were not observed owing to the large bandwidth of the Raman bands. The Raman studies suggest, therefore, that the structure of the unknown phase, existing below 553 K, differs slightly form the orthorhombic structure present above 553 K. The pressure-dependent study revealed that the 52 cm(-1) band, assigned to external vibrations of the WO6 octahedron, consists at ambient temperature and pressure of two overlapping bands. These bands become well separated at high pressure. Copyright (C) 2003 John Wiley Sons, Ltd.

@article{WOS:000181640000003, abstract = {Pressure- and temperature-dependent Raman studies were performed on KNbW2O9 ferroelectric hexagonal tungsten bronze single crystal. The results suggest that some structural changes, possibly phase transitions, connected with tilting of the WO6 octahedra occur in this material at around 290-350 K and 1.0-1.4 GPa. No changes in the spectra could be observed at the 523 and 543-553 K phase transitions. The data indicate that these phase transitions lead to only weak changes in the vibrational properties of KNbW2O9, which were not observed owing to the large bandwidth of the Raman bands. The Raman studies suggest, therefore, that the structure of the unknown phase, existing below 553 K, differs slightly form the orthorhombic structure present above 553 K. The pressure-dependent study revealed that the 52 cm(-1) band, assigned to external vibrations of the WO6 octahedron, consists at ambient temperature and pressure of two overlapping bands. These bands become well separated at high pressure. Copyright (C) 2003 John Wiley Sons, Ltd.}, added-at = {2022-05-23T20:00:14.000+0200}, address = {BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND}, author = {Maczka, M and Souza, AG and Freire, PTC and Mendes, J and Kojima, S and Hanuza, J and Majchrowski, A}, biburl = {https://www.bibsonomy.org/bibtex/2113b64c1ba7675e48c0f96707b4e8ae2/ppgfis_ufc_br}, doi = {10.1002/jrs.957}, interhash = {065cc76984137fb4037843d3a0958a2a}, intrahash = {113b64c1ba7675e48c0f96707b4e8ae2}, issn = {0377-0486}, journal = {JOURNAL OF RAMAN SPECTROSCOPY}, keywords = {bronze} ferroelectrics; hexagonal phase spectra; transitions; tungsten {Raman}, number = 3, pages = {199-204}, publisher = {JOHN WILEY & SONS LTD}, pubstate = {published}, timestamp = {2022-05-23T20:00:14.000+0200}, title = {Pressure- and temperature-dependent Raman studies of KNbW2O9 hexagonal tungsten bronze}, tppubtype = {article}, volume = 34, year = 2003 }