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The electrical and optical properties of (001)‐ and (110)‐oriented 0.73 Pb(Mg1/3Nb2/3)O3‐0.27PbTiO3 single crystals are systematically investigated at various temperatures, both of which present a series of ferroelectric phase transition processes. Dielectric performance measurements reveal that the ferroelectric phase transition occurs over a temperature range, rather than at one temperature point. By testing the ferroelectric hysteresis P–E curves as well as bipolar and unipolar electric field‐induced strain S–E curves, the values of remnant polarization, coercive field, maximum strain, and converse piezoelectric constant d33* change considerably near the phase transition temperatures. Simultaneously, the 0.73PMN‐0.27PT single crystals with (001)‐ and (110)‐orientations under a low electric field show ultrahigh d33* values of 3540 and 2817 pm/V, respectively, which can be attributed to the electric field‐induced monoclinic and orthorhombic phases, respectively. The series of ferroelectric phase transitions upon heating, that is, from rhombohedral ferroelectric to monoclinic/orthorhombic, followed by from monoclinic/orthorhombic to tetragonal, and finally from tetragonal to cubic paraelectric, are further investigated via polarized light microscopy and Raman spectroscopy. The 0.73PMN‐0.27PT single crystals present a series of ferroelectric phase transition processes, which is confirmed by dielectric performance measurement, polarized light microscopy and Raman spectra contour plot. The electric field induced monoclinic and orthorhombic phase contribute to the ultra‐high d33- in the (001)‐ and (110)‐orientations crystals. [ABSTRACT FROM AUTHOR]

Using the polycrystalline material with a nominal composition of Nd0.01Pb0.985[(Mg1/3Nb2/3)0.70Ti0.30]O3, an Nd-doped PMN–PT single crystal has been grown successfully by a vertical Bridgman process. The perovskite structure and the crystalline phase evolution of the as-grown crystal were confirmed by X-ray diffraction analysis. A series of (001)-oriented crystal wafers, fabricated from different regions of the as-grown crystal boule, were characterized systematically to verify their electrical properties. Compared to the undoped PMN–PT single crystal, the crystal wafers under direct current polarization exhibited an improved piezoelectric coefficient d33 of 1780–2870 pC N−1, along with a lower phase transition temperature T and a lower Curie temperature Tc in the range of 55–63 °C and 95–141 °C, respectively. The coercive field Ec and the remnant polarization Pr for the crystal wafers were measured to be 1.7–2.7 kV cm−1 and 23.9–32.7 μC cm−2, respectively. It was found that the piezoelectric coefficient d33 of the crystal wafer could be even elevated to the range 2200–3650 pC N−1 by applying alternating current polarization. The improved piezoelectricity for the crystal wafer under alternating current polarization may be associated with the increased domain density inside the crystal medium. [ABSTRACT FROM AUTHOR]

An optimal annealing condition (360 °C, 10 min) was found for the FeBSiC Metglas, at which the Metglas transformed into a mix phase structure between amorphous and crystalline. It gives a deformation of single-layer FeBSiC Metglas ribbon increases from 26.9 ppm of the unannealed sample to 34.6 ppm, piezomagnetic coefficient d33,m from 1.9 to 2.6 ppm/Oe, and the loss decreases from 0.18 to 0.07%. After the mix phase Metglas and Mn-doped 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (Mn-doped PMN-PT) single crystal were fabricated into a magnetoelectric (ME) laminate composite, it is found that αQ at quasi-static and resonance frequency rises from 2183 to 2640 pC/Oe, and from 120,000 to 165,000 pC/Oe, with the increase amplitude of 21% and 37.5%, respectively. From test of realistic noise, the equivalent noise magnetic field (EMN) @1 Hz of the ME sensor made by mix phase Metglas declines from 20.2 to 15.4 pT/Hz1/2, and EMN@30 Hz from 1.46 to 1.23 pT/Hz1/2. The reinforcement of the piezomagnetic performance is attributed to the generation of mix phase structure. It can enhance ME coupling performance at quasi-static and resonance state, reduce loss, and boost the sensitivity of the ME sensor. [ABSTRACT FROM AUTHOR]

The fatigue resistance of pseudo-ternary single crystal 0.22Pb(In 1/2 Nb 1/2)O 3 -0.53Pb(Mg 1/3 Nb 2/3)O 3 -0.25PbTiO 3 (PIMNT) is tested by a "two-step poling process" – alternate current poling (ACP) with different cycles followed by direct current poling (DCP). The remnant polarization of the hysteresis loop decreases significantly and then does not change, and the coercive field raises with increasing polarization cycles. However, the two-step poling process contributes to the optimization and stability of fatigue resistance. Before 700 cycles, the piezoelectric constant d 33 of the crystal is obviously promoted compared with the conventional DCP sample of d 33 = 2200 pC/N, which increases by 40.9%–3100 pC/N, while the average thickness mode electromechanical coupling coefficient K t remains at 0.518. With the increase in number of polarization cycles, the d 33 and K t are larger and more stable than for the ACP only sample. This improvement is due to nanoscale denser and smaller domains induced by the two-step poling process. • Two-step poling process gives single-crystal PIMNT good performance, stability and fatigue resistance. • Before 700 cycles, the process increases d 33 from 2200 to 3100 pC/N and average K t remains at 0.518 • The d 33 and K t of PIMNT after this process are larger and more stable than single AC aging. • The process reduces domain size to nanoscale and domains become denser and smaller. [ABSTRACT FROM AUTHOR]