Angle-resolved polarized Raman scattering on relaxor ferroelectrics with intermediate random fields

Abstract

The analysis of the local structure formed by random fields in relaxor ferroelectrics is of technical and fundamental importance in understanding the origin of colossal piezoelectricity. We determined the temperature, electric field, and angular dependences of polarized Raman scattering in Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 single crystals. The dependence of the intensity of a Raman active mode on the rotation angle of a polarization plane is measured in a paraelectric cubic phase. These angular dependences are calculated theoretically by assuming the local R3m symmetry to compare the experimental data. The applied electric field in a paraelectric cubic phase suppresses the random fields and therefore the change in the ratio of Raman tensor components from the result at zero field is observed. At a sufficiently higher electric field, the angular variation changes perfectly from its zero field behavior. This indicates the appearance of tetragonal symmetry induced by an electric field.

Temperature-gradient investigation of phase transitions in ferroelectrics using cooling and heating stage

“…Raman scattering data were acquired using our system, which comprises a polarization rotation system installed in a microscope. 25,[28][29][30][31][32] A BaTiO 3 crystal was placed in the cooling and heating stage (with a quartz glass window) on an XYZ mapping stage installed in the microscope. Using a 10x objective lens, the focus was about 10 μm in diameter on the sample.…”

Morphotropic phase boundaries of (1−x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 probed by Raman spectroscopy at high temperature

“…Raman scattering was measured using our home-built system composed of a polarization rotation system installed on a microscope. 36,39,40) The crystals were placed inside a temperature-controlled cell (Linkam) on an xyz mapping stage (Tokyo Instruments) installed on the microscope (Olympus). Linearly polarized light from a diode-pumped solid state laser (Spectra Physics) with single frequency operation at 532 nm and power of 200 mW traveled to the sample through a polarization rotation device (Sigma Koki) equipped with a broadband half-wave plate (Kogakugiken) in the microscope.…”

Aging effect in Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystal

“…11) On the other hand, solid solutions in relaxors and classical ferroelectrics, typified by PMN-xPT and PZN-xPT, so called the relaxor ferroelectrics, attracted much attention because of their unique physical properties such as a diffuse phase transition. [14][15][16][17][18] Such diffuse phase transition in relaxor ferroelectrics was proposed to come from the heterogeneous structure, where a lot of small ferroelectric domains, so called polar nanoregions (PNRs), were assumed to exist in the paraelectric matrix. 19,20) In fact, PNRs in PMN and PMN-xPT were observed by means of the transmission electron microscopy 21) and the piezoelectric force microscopy.…”