Qirong Yao

Electric Field-Induced Giant Strain and Photoluminescence-Enhancement Effect in Rare-Earth Modified Lead-Free Piezoelectric Ceramics

In this work, an electric field-induced giant strain response and excellent photoluminescence-enhancement effect was obtained in a rare-earth ion modified lead-free piezoelectric system. Pr(3+)-modified 0.93(Bi0.5Na0.5)TiO3-0.07BaTiO3 ceramics were designed and fabricated by a conventional fabrication process. The ferroelectric, dielectric, piezoelectric, and photoluminescence performances were systematically studied, and a schematic phase diagram was constructed. It was found the Pr(3+) substitution induced a transition from ferroelectric a long-range order structure to a relaxor pseudocubic phase with short-range coherence structure. Around a critical composition of 0.8 mol % Pr(3+), a giant reversible strain of ∼0.43% with a normalized strain Smax/Emax of up to 770 pm/V was obtained at ∼5 kV/mm. Furthermore, the in situ electric field enhanced the photoluminescence intensity by ∼40% in the proposed system. These findings have great potential for actuator and multifunctional device applications, which may also open up a range of new applications.

Large electrostrictive effect in ternary Bi0.5Na0.5TiO3-based solid solutions

In the present work, a ternary solid solution (0.935-x)Bi0.5Na0.5TiO3-0.065BaTiO3-xSrTiO3 (BNBST, BNBSTx) was designed and fabricated using the traditional solid state reaction method. A morphotropic phase boundary between the ferroelectric long-range-order and relaxor pseudocubic phases was determined around x of 0.22 for poled solid solutions. The further increase of SrTiO3 substitution turned the depolarization temperature Td to below ambient temperature and led to a sharp decrease in the remnant polarization Pr and quasi-static piezoelectric constant d33. A large electrostrictive coefficient Q of 0.026 m4 C−2 was obtained for BNBST0.30, which was entirely comparable to the well-known electrostrictive material Pb(Mg1/3Nb2/3)O3, recently reported Bi0.5Na0.5TiO3-BaTiO3-K0.5Na0.5NbO3, and Bi0.5Na0.5TiO3-BaTiO3-KNbO3. Under a moderate electric field of 4 kV/mm, the electrostrictive strain can reach as high as ∼0.11%. Furthermore, the electric-field-induced strain exhibited weak temperature-dependent behavi...

Magnetic and Electrical Properties of Zr-rich (1-x)PZT+xBiFeO3 Ceramics

We reported multiferroic ceramics (1-x)PZT +xBiFeO3 (x = 0.01–0.10, Zr/Ti = 95/5–100/0) were prepared by a conventional solid-state reaction process. The structures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD showed that the (1-x)PZT+xBiFeO3 samples formed perovskite structure. SEM indicated that the dense ceramics were obtained when the sintering process was modified. It is well known that the PZT95/5 system is a typical ferroelectric material and BiFeO3 possesses antiferromagnetic property. It was found that (1-x)PZT+xBiFeO3 exhibited both ferroelectric and ferromagnetic properties at room temperature. The relationship between the ferroelectric and ferromagnetic properties was discussed.

Large strain response in PZT-PZN-PAN lead-based ceramics

Solid solutions of 0.8Pb(Zr0.52Ti0.48)O3-(0.2-x)Pb(Zn1/3Nb2/3)O3-xPb(Al1/2Nb1/2)O3 (PZT-PZN-PAN, PZT-PZN-xPAN) with x from 0 to 0.1 were fabricated and the dielectric, ferroelectric, piezoelectric properties were investigated in detail. Results show the crystal structure changes from coexists of tetragonal and rhombohedral to single rhombohedral phase. At a critical composition of 0.02, a maximum quasi-static piezoelectric coefficient d33 (410 pC/N) was obtained. Furthermore, it is found that the increment of PAN content could lead to increase the strain of PZT-PZN-xPAN ceramics, and a large strain response of ~0.24% with normalized strain Smax/Emax as high as 767 pm/V was obtained for the PZT-PZN-0.1PAN under a low electric field of ~3 kV/mm, which makes it a promising material for solid-state actuator applications.