Phase transformation in BST ceramics investigated by internal friction measurements

Ferroelectric (BaSr)TiO3 materials are widely used for numerous applications in microelectronic ranges. This paper concerns investigation of variation of internal friction and shear modulus versus temperature in a low frequency range for BaxSr1−xTiO3 systems (x = 0.4, 0.55, 0.7 and 0.8). This makes it possible to report energy dissipation phenomena such as phase transitions and relaxation processes due to interactions between domain walls and oxygen vacancies. Temperature of loss peak for each phase transition decreases and peaks become more diffuse with increasing Sr content in BST materials. An experimental phase diagram has been established for BaxSr1−xTiO3 systems. Effects of MgO doping have been investigated for the composition x = 0.8. Both level of mechanical loss and temperatures of phase transitions are sensitive to the Mg dopant.