0000000000014711
AUTHOR
Roman Rosiek
LEAD-FREE (Na0.5Bi0.5)1-xBaxTiO3 SINGLE CRYSTALS (0 ≤ x ≤ 0.05) AND THEIR DIELECTRIC AND PYROELECTRIC PROPERTIES
ABSTRACT Lead-free single crystals of Na0.5Bi0.5TiO3-BaTiO3 (NBT-BT) system were prepared by Czochralski method and their dielectric and pyroelectric properties have been studied. The results were compared with these for pure NBT. The obtained samples show pure perovskite structure with rhombohedral symmetry at room temperature. Low frequency (100 Hz–100 kHz) investigations reveal the diffuse phase transitions. The obtained results are discussed in terms of local electric and strain fields caused by different ionic radius of (Na, Bi) and Ba ions. The NBT-BT system is expected to be a new promising candidate for lead-free electronic crystals.
Influence of Unaxial Pressure on Electric Properties of (1-x)PSN-xPLuN Solid Solutions (0.75 ≤ x < 1)
(1-x)PSN-xPLuN ceramics with single phase perovskite structure and rhombohedral symmetry at room temperature were prepared by solid-state reaction method. The influence of unaxial pressure (0–1500 bars) on dielectric properties of these compounds were studied. It is found that these materials are sensitive to external stress. This includes the shift of phase transitions, diffuseness of dielectric permittivity characteristics and the decrease of the thermal hysteresis of the permittivity and field-polarization hysteresis. These changes of properties could be connected with the change in domain structure, the elastic change of distances between ions and the change in defects density.