Stress-modified phase transitions in polarized PMN-PIN-PT, KN and KNL-NTS single crystals/textured ceramics: Thermal expansion and Raman scattering studies

Piezoelectric PMN-PIN-PT as well as lead-free KN and KNL-NST analogues in the form of single crystals or textured ceramics were investigated as a function of temperature and/or applied stress using Raman spectroscopy and dilatometry. The results reveal: 1) the 1
^st
order character of the 120°C-transition in PMN-PIN-PT; 2) a previously unreported stress dependent phase transition in KN at 70°C; 3) important structural and dielectric changes in the case of KNL-NST ceramics in comparison with KN.