@article{yamashita_yamagata_xiang_maiwa_xu_jiang_2024, title={Comparison of field-cooling DC poling and AC poling for lead perovskite relaxor-PbTiO<sub>3</sub> single crystals grown by a continuous feeding Bridgman process}, volume={63}, ISSN={["1347-4065"]}, DOI={10.35848/1347-4065/ad2fe0}, abstractNote={Abstract We investigated the effectiveness of poling processes for Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 single crystals (SCs) produced using a continuous feeding Bridgman method, which is known to produce a high property uniformity. The four studied poling processes are: (I) standard direct current poling (STD-DCP); (II) low-voltage field-cooling DCP (LV-FCP); (III) high-voltage field-cooling DCP (HV-FCP); and (IV) mid-temperature alternating current poling (MT-ACP). The highest free dielectric constant ( ε 33 T / ε 0 ) and piezoelectric constant ( d 33 ) were obtained by MT-ACP ( ε 33 T / ε 0 = 11 000, d 33 = 3000 pC/N), followed by LV-FCP ( ε 33 T / ε 0 = 7500, d 33 = 2400 pC/N), HV-FCP ( ε 33 T / ε 0 = 6250, d 33 = 1850 pC/N), and STD-DCP ( ε 33 T / ε 0 = 6200, d 33 = 1800 pC/N). The LV-FCP SC showed a 21% and 33% increase in ε 33 T / ε 0 and d 33 compared to that of the STD-DCP SC; however, this was not as much as the 77% and 67% improvement of the MT-ACP SC. These results provide guidance for SC transducers.}, number={4}, journal={JAPANESE JOURNAL OF APPLIED PHYSICS}, author={Yamashita, Yohachi and Yamagata, Yushi and Xiang, Yu and Maiwa, Hiroshi and Xu, Zhengze and Jiang, Xiaoning}, year={2024}, month={Apr} }
 @article{kim_zhang_wang_wu_xu_liu_moon_yamashita_ryu_liu_et al._2024, title={Electrical de-poling and re-poling of relaxor-PbTiO<sub>3</sub> piezoelectric single crystals without heat treatment}, volume={15}, ISSN={["2041-1723"]}, url={https://doi.org/10.1038/s41467-024-50847-3}, DOI={10.1038/s41467-024-50847-3}, abstractNote={Re-poling of unexpected partially depoled piezoelectric materials conventionally needs to be first fully depoled through annealing above their Curie temperature to revive piezoelectric performances. Here, we investigated de-poling and re-poling of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals under electric fields at room temperature. We found that alternating current electric fields with amplitudes near the coercive field at low frequencies (<10 Hz) can be employed to successfully depolarize poled crystals at room temperature. We also demonstrated a reversible polarization switching process with a relaxor-PbTiO3 single crystal ultrasound transducer without device performance degradations. This experimental observation is supported by phase-field simulation, showing that alternating current electric fields can readily induce de-poling at room temperature, while direct current electric fields induce a transient depoled state only within an uncontrollable short period of time. The findings suggest new strategies for unprecedented in-device tailoring of the polarization states of ferroelectric materials. The authors find that alternating current electric fields with amplitudes near the coercive field at low frequencies (<10 Hz) can be employed to depolarize poled relaxor-PbTiO3 single crystals at room temperature, without conventional heat treatment.}, number={1}, journal={NATURE COMMUNICATIONS}, author={Kim, Hwang-Pill and Zhang, Mao-Hua and Wang, Bo and Wu, Huaiyu and Xu, Zhengze and Liu, Sipan and Moon, Sunho and Yamashita, Yohachi and Ryu, Jong Eun and Liu, Jun and et al.}, year={2024}, month={Jul} }
 @article{yamashita_kurita_tanaka_xiang_maiwa_lim_xu_liu_jiang_2024, title={Enhanced piezoelectrical properties of Pb(Zn<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub> - PbTiO<sub>3</sub> single crystals by AC poling}, volume={63}, ISSN={["1347-4065"]}, DOI={10.35848/1347-4065/ad6452}, abstractNote={Abstract We investigated the effectiveness of AC poling (ACP) processes for [001] direction oriented Pb(Zn1/3Nb2/3)O3-0.055PbTiO3 (PZN-PT) single crystals (SCs) and obtained dielectric constant ε33T/ε0 of 6680 and piezoelectric strain constant d33 of 2760 pC/N, piezoelectric charge constant g33 of 46.7 × 10-3Vm/N, and a figure of merit (FOM) (d33 × g33) of 129 × 10-12m2/N. These values were 19%, 31%, 10%, and 45% higher than those of DC poling PZN-PT SC, respectively. Phase change temperature Tpc, Curie temperature Tc, and acoustic impedance (Z33) of the ACP PZN-PT SC were 121 oC, 165 oC, and 30.5 MRayls, respectively. Compared with Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 SCs, the higher Tpc, Tc, FOM and lower Z33 of the PZN-PT SCs enable the applications in high temperature with better Z33 matching to water and human body, and these findings are vital for a wide range of ultrasonic transducer applications.}, number={8}, journal={JAPANESE JOURNAL OF APPLIED PHYSICS}, author={Yamashita, Yohachi John and Kurita, Ibuki and Tanaka, Mario and Xiang, Yu and Maiwa, Hiroshi and Lim, Leong-Chew and Xu, Zhengze and Liu, Sipan and Jiang, Xiaoning}, year={2024}, month={Aug} }