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(1- x)Pb(Mg 1/3 Nb 2/3)O 3 - x PbTiO 3 (PMN-PT) single crystals, especially with compositions near its morphotropic phase boundary (MPB), have been employed for a broad range of applications such as ultrasound transducers, sensors, and actuators. To further enhance the properties of PMN-PT, electrode patterning, as a method of domain engineering, was proved to be an effective approach. In our previous report, a 200 nm grating pattern electrode (Ti/Au–MnO x) (nano-electrode) was prepared on one surface of PMN-PT crystal, exhibiting 30% d 33 enhancement. In this work, the multi-layered domain morphology and the domain engineering from nano-electrode were characterized using piezoresponse force microscopy (PFM). A hypothetical domain engineering model for nano-electrodes is established to explain the experimental results as well as the property enhancement from the nano-electrode. The electrode patterning proves that the nano-scale modification can tune the macro-scale piezoelectric properties of the bulk material. Image, graphical abstract Nano-patterned composite electrode (Nano-electrode) , as a method of domain engineering, exhibits 30% d 33 enhancement on (1- x)Pb(Mg 1/3 Nb 2/3)O 3 - x PbTiO 3 (PMN-PT) single crystal. In this work, the mechanism of the property enhancement is studied through the multi-layered domain morphology by piezoresponse force microscopy (PFM). A hypothetical domain engineering model for nano-electrodes is established in the end. [ABSTRACT FROM AUTHOR]

The domain structure, dielectric, and piezoelectric properties of 0.7 Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 (PMN-PT) single crystals with nanocomposite electrode, which includes MnO x semiconductor nanogratings and a Ti/Au conductive layer, were studied in this paper. These artificial MnO x nanogratings can alter the electric field distribution and then enhance the domain density. PMN-PT crystals with Ti/Au-MnO x nanocomposite electrodes showed high piezoelectric constant of 2250 p.m./V and dielectric constant of 5400 at 1 kHz, respectively. Compared to ones with conventional planar electrodes, the piezoelectric and dielectric constants of the samples with nanocomposite electrodes were increased 36.7% and 38.3%, respectively. Piezoresponse force microscopy (PFM) images revealed the domain pattern near the electrode/single crystal interface. A linear domain structure induced by the MnO x nanocomposite electrode was found in the samples with thickness less than 200 μm. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) results showed the diffusion of Mn about 300 nm in depth in PMNPT crystal after heat treatment during MnO x nanocomposite electrode. It is believed that the localized high electric fields induced by fringe effects caused by the nanocomposite electrode can enhance nucleation of new domains, and that diffusion from the patterned Mn layer may also lead to an enhancement in domain wall mobility. Our findings open up a new domain engineering technique for tailoring the dielectric and piezoelectric properties of PMN-PT single crystals. [ABSTRACT FROM AUTHOR]

Sliver-mode 0.73Pb(Mg 1/3 Nb 2/3)O 3 -0.27PbTiO 3 single crystals were poled by the alternating current electric field (ACP) along the [001] direction for low-frequency transducer applications. Under ACP with optimized conditions (2.89 kV rms , 0.1 Hz, 10 cycles), the free dielectric constant (ε T 33 / ε 0) was enhanced from 5300 to 7220 and piezoelectric coefficient (d 33) was improved from 1410 to 1920 pC/N, both are about 36% higher than those under traditional direct current poling. The piezoresponse force microscopy observation and phase-field simulation show the similar domain morphologies evolution. During the ACP process, the domain morphology first changes from '4R' to '2R' configuration, and then the length of the 109° domain wall keeps increasing, which leads to a longer range of ordering and a stable lamellar domain structure in the end. The correlation between the domain morphology and the coercive field is also found in both the experiment and simulation. These findings on the effect and mechanism of ACP will help develop advanced low-frequency single crystal transducer arrays. Evolution of domain structures of rhombohedral PMN-PT during ACP process was studied through the domain morphology tracking, which developed from '4R' to '2R' configuration. The results also show a good correlation between coercive field and domain structure, attributing to a new domain engineering model. [Display omitted] [ABSTRACT FROM AUTHOR]