Electrostrain in excess of 1% in polycrystalline piezoelectrics

Abstract

Piezoelectric actuators transform electrical energy into mechanical energy, and because of their compactness, quick response time and accurate displacement, they are sought after in many applications. Polycrystalline piezoelectric ceramics are technologically more appealing than single crystals due to their simpler and less expensive processing, but have yet to display electrostrain values that exceed 1%. Here we report a material design strategy wherein the efficient switching of ferroelectric-ferroelastic domains by an electric field is exploited to achieve a high electrostrain value of 1.3% in a pseudo-ternary ferroelectric alloy system, BiFeO-PbTiO-LaFeO. Detailed structural investigations reveal that this electrostrain is associated with a combination of several factors: a large spontaneous lattice strain of the piezoelectric phase, domain miniaturization, a low-symmetry ferroelectric phase and a very large reverse switching of the non-180° domains. This insight for the design of a new class of polycrystalline piezoceramics with high electrostrains may be useful to develop alternatives to costly single-crystal actuators.

Investigation of dielectric and piezoelectric properties in aliovalent Eu3+‐modified Pb(Mg1/3Nb2/3)O3‐PbTiO3 ceramics

“…This is due to the fact that the rhombohedral phase with a smaller lattice deformation is more easily rotated when compared to their tetragonal counterparts, resulting in a larger strain under lower electric field, while at higher electric field, the domain switch is clamped thus less contribution from the domain wall motion. However, the tetragonal phase with larger lattice deformation (c/a ratio) will produce larger strain at higher electric field …”

High electromechanical response in the non morphotropic phase boundary piezoelectric system PbTiO3−Bi(Zr1/2Ni1Pandey1, Narayan2, Khatua3 et al. 2018Phys. Rev. BSelf Cite282110View full textAdd to dashboardCite

“…3b). Recently, Bastola et al reported a very large electrostrain (greater than 1 %) in a similar system (La modified BiFeO3-PbTiO3, BF-PT:La) [57]. This particular system is also non-MPB in nature.…”

“…The electrostrain increases sharply when the random-field due to La substitution starts miniaturizing the P4mm domians, which manifests as the onset of a CL phase on the global scale [57]. The extraordinary electrostrain (> 1 %) in BF-PT:La is due to a combination of large tetragonality (c/a ~ 2.2 %), high mobility of the tetragonal domain walls as the CL phase sets in [57], and very large reverse switching of the tetragonal domians [61,62]. This discovery further confirms that polarization rotation and field induced interferroelectric transformation is not necessary for achieving large electromechanical response in piezoceramics.…”

Low‐temperature sintering of BF‐PT‐BZ ternary solid solutions with enhanced piezoelectric properties

“…Ion doping is widely used to improve insulation resistance, reduce c/a ratio, and improve piezoelectric properties of BF‐PT ceramics. For example, La‐modified BF‐PT ceramics have been reported to possess the resistivity of about 10 13 Ω cm, a high d 33 value of 297 pC/N, and a giant strain over 1% . Most recently, the ternary system has been designed to reduce the c/a ratios and improve piezoelectric properties of BF‐PT based ceramics.…”

“…For example, La-modified BF-PT ceramics have been reported to possess the resistivity of about 10 13 Ω cm, a high d 33 value of 297 pC/N, and a giant strain over 1%. 6,7 Most recently, the ternary system has been designed to reduce the c/a ratios and improve piezoelectric properties of BF-PT based ceramics. The third end-members, such as PbZrO 3 , 8,9 Bi(Zn 1/3 Ti 2/3 )O 3 , 10,11 BaTiO 3 ,12,13 BaZrO 3 , [14][15][16][17] and Ba(Zr 0.25 Ti 0.75 )O 3 , 18 have been incorporated with BF-PT binary ceramics making the most interesting materials for high-performance piezoelectric applications.…”