Thermal expansion and polarization of (1-x)PNNxPT solid solutions

The paper presents the results of detailed studies of the thermal expansion of (1-x)PbNi1/3Nb2/3O3-xPbTiO3 solid solutions with x¼0- 0.8. The anomalous and lattice contributions to deformation and the thermal expansion coefficient are analyzed and the mean square polarization Pd is determined. The results obtained are discussed within the framework of the thermodynamic theory and the Landau 2-4-6 coefficients for solid solutions are estimate

LOCAL PIEZOELECTRICITY IN SrTiO3-BiTiO3 CERAMICS

Local piezoelectric properties of Bi-doped SrTiO3 ceramics have been investigated by piezoresponse force microscopy. The appearance of both out-of-plane and in-plane polarization components confirmed the piezoelectric nature of the obtained signal. The absence of labyrinth-like structures in observed piezoelectric contrast is not consistent with the expected existence of a relaxor ferroelectric state in this material. The close similarity of local piezoelectric properties in Bi-doped SrTiO3 with pure SrTiO3 suggests that the origin of obtained piezoresponse can be attributed to the flexoelectric phenomenon. Bi-doping leads to occurrence of oxygen vacancies and negative charge on the surface of the sample

Thermal expansion and polarization of (1-x)PNN-xPT solid solutions

The paper presents the results of detailed studies of the thermal expansion of (1-x)PbNi1/3Nb2/3O3-xPbTiO3 solid solutions with x = 0-0.8. The anomalous and lattice contributions to deformation and the thermal expansion coefficient are analyzed and the mean square polarization Pd is determined. The results obtained are discussed within the framework of the thermodynamic theory and the Landau 2-4-6 coefficients for solid solutions are estimated

Dielectric Response in (K0.5Na0.5) (Nb 1-xSbx)O3+0.5 mol%MnO2 Ceramics to Weak Sinusoidal Fields of Low and Infra-Low Frequencies

The thermal anomalies exhibited as "shoulders" at infra-low frequencies and maximums at low frequencies related to structural transitions in the polar phase of (K0.5Na0.5) (Nb1-xSbx) O3+0.5 mol%MnO2 are found to shift from T ∼ 185°C to T ∼ 140°C at changing concentration x from 0 to 0.05. The range of temperature ΔT(x) corresponding to the difference between positions of the anomalies on the '(T) curve at frequencies 1000 Hz and 1 Hz changes from 0.5 degrees at x = 0 to 2.5 degrees at x = 0.05, which may point to relaxor properties of the given phase transition being present only at rather high concentrations of Sb

Polar Phonons in Relaxor Ferroelectric 0.2PSN-0.4PMN-0.4PZN

Relaxor ferroelectrics $0.2PbSc_{1//2}Nb_{1//2}O_3-0.4PbMg_{1//3}Nb_{2//3}O_3-0.4PbZn_{1//3}Nb_{2//3}O_3$ ceramics were studied by means of the Fourier transform infrared reflection and THz transmission spectroscopy in the temperature range of 20-500 K. On heating from low temperatures, the $A_1$ component of the strongly split $TO_1$ mode softens towards the Burns temperature, but the softening ceases near 400 K, which could be a signature of polar cluster percolation temperature

Terahertz Spectroscopy of Ordered PbSc1//2Nb1//2O3PbSc_{1//2}Nb_{1//2}O_3 Ceramics

The ordered $PbSc_{1//2}Nb_{1//2}O_3$ ceramics were studied by THz transmission spectroscopy in the temperature range of 80-300 K. Below ferroelectric phase transition temperature the strength of central mode gradually decreases and gives evidence for a mixed displacive and order-disorder character of the transitions. Ferroelectric phase transition is connected with an abrupt freezing and rise of polar nanoregions into ferroelectric domains