Time-Resolved Nanobeam X-ray Diffraction of a Relaxor Ferroelectric Single Crystal under an Alternating Electric Field

Lead-containing relaxor ferroelectrics show enormous piezoelectric capabilities relating to their heterogeneous structures. Time-resolved nanobeam X-ray diffraction reveals the time and position dependences of the local lattice strain on a relaxor ferroelectric single crystal mechanically vibrating and alternately switching, as well as its polarization under an alternating electric field. The complicated time and position dependences of the Bragg intensity distributions under an alternating electric field demonstrate that nanodomains with the various lattice constants and orientations exhibiting different electric field responses exist in the measured local area, as the translation symmetry breaks to the microscale. The dynamic motion of nanodomains in the heterogeneous structure, with widely distributed local lattice strain, enables enormous piezoelectric lattice strain and fatigue-free ferroelectric polarization switching.

Recent progress on AC poling of relaxor-PbTiO3 ferroelectric single crystals (Review)

Compared with conventional DC poling (DCP) treatment, a novel technology, AC poling (ACP) treatment was proved in 2014 as a low-cost, time-saving, and smart-process method to significantly enhance properties of relaxor-PbTiO3 (PT) ferroelectric single crystal (SC) transducers. In total, over 35 papers have been reported since 2018 in which researchers achieved piezoelectric coefficient (d 33) > 4000 pC/N and electromechanical coupling factors (k 33) > 96% for the ACP SCs. In this review, we introduce history of the ACP study on relaxor-PT SCs and our research group's ACP study in the past three years. Particularly, we focus on ACP conditions and their mechanisms of binary (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) and ternary (1-x-y)Pb(In1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)O3-xPbTiO3 (PIN-PMN-PT) SCs near morphotropic phase boundary (MPB). Furthermore, we provide insights for further studies on optimal ACP conditions and the reduction of spurious-mode vibrations (SMV). This work can offer promising prospect and practical value in the high-end ultrasonic imaging probe transducers

High-accuracy polarimetric studies on lead germinate single crystals

A high-accuracy polarimetric technique has been used for the characterization of a lead germanate ferroelectric single crystal. The measurement results of the linear and circular birefringence in the [010] direction at a wavelength of 633 nm under the influence of an electric field are presented. Gyration–electric field hysteresis loops at alternative crystal positions in the polarization system have been used to determine the ellipticity of the eigenwaves. A temperature dependence of the gyration tensor component g 11 in the temperature range of 300–450 K was found.

Optical Properties and Band Gap of Ternary PSN-PMN-PT Single Crystals

This study investigated the optical properties and the interband transition of a ternary [100]-oriented 6PSN-61PMN-33PT relaxor ferroelectric single crystal. Compared with the binary [100]-oriented PMN-32PT crystal, the [100]-oriented 6PSN-61PMN-33PT crystal exhibited excellent optical properties, including high transmittance, low refractive index, weak frequency dispersion, and low reflection and absorption coefficients. All these differences can be attributed to the structural changes of the 6PSN-61PMN-33PT crystal, such as its large lattice size and increased band gap. The crystal’s transmittance was significantly improved after alternating current electric field poling due to the increased domain size and the order domain structure. The largest transmittance for the 6PSN-61PMN-33PT crystal was up to 66%. Our experimental results indicate that the ternary 6PSN-61PMN-33PT ferroelectric single crystal has great application potential in the optical field.

Bridgman Growth and Photoelectronic Property of Relaxor-Based Ferroelectric Single Crystal Pb(Sm1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3

A relaxor-based ferroelectric single crystal with the nominal composition of xPb(Sm0.5Nb0.5)O3-(0.7‒x) Pb(Mg1/3Nb1/3)O3-0.3PbTiO3 (x = 0.01, 0.02, and 0.03) was grown by the vertical Bridgman process. The electrical properties and the ferroelectric domains, as well as the luminescent characteristics of the single crystals, were investigated systematically. The piezoelectric coefficient d33 of the single crystals are slightly higher than that of the undoped PMN-PT single crystal under direct current polarization, while the crystal wafers gain a much higher d33 value upon being polarized with alternating current voltage. The single crystals possess a decreased phase transition temperature of around 60 °C and a decreased Curie temperature of 92~116 °C compared with the undoped PMN-PT single crystal. The crystal wafers polarized with alternating current voltage exhibited a desirable optical transmittance, which is associated with the domain structure changes inside the crystal medium. The domain density of the crystal wafers under alternating current polarization was significantly decreased compared with the direct current polarized crystal wafers. The luminescent spectra of the crystal wafers exhibit the typical emission peaks corresponding to the characteristic transition of Sm3+ ions in the crystal lattice.

Tunable LiNbO3-based diffractive optical element for the control of transverse modes of a laser beam

A diffractive optical element based on a nonlinear-optical ferroelectric single crystal has been proposed, synthesized, and experimentally characterized. The element allows fast modulation of transverse modes of a Gaussian laser beam.

Magnetic Pre-Loading for a Tonpilz-Type Acoustic Projector

This paper describes a new magnet-based method for applying a compressive pre-load to the piezoceramic elements of a Tonpilz-type acoustic projector, with the advantage of lower damping due to mechanical friction and a greater range of unhampered resonant motion since no plate spring is required. The Tonpilz-type acoustic projector can be applied to structural health monitoring studies involving air coupled ultrasound. Acoustic model predictions and the measured behaviour of a relaxor ferroelectric single crystal (RFSC) based prototype device, operating in air, are presented and show good correlation. With a 5 V drive, at 9420 Hz resonance, the prototype device generates a sound pressure level of 113 dB measured at an axial distance of 5 mm. The maximum peak tip displacement of the device’s head mass is predicted to be 0.7 µm at resonance. This is well within the 2 µm displacement produced by the 90 N magnetic pre-load, thus protecting the RFSC ceramic element from damaging tensile stress.