Effects of site engineering and doped element types on piezoelectric and dielectric properties of bismuth ferrite lead-free ceramics

Abstract

Poor piezoelectric activity is often observed in BiFeO 3 ceramics due to its low resistivity and high coercive field, which easily results in the break down before the domains are switched. Here, we attained a high piezoelectricity using a series of bismuth ferrite ceramics substituted by rare earth elements and transition metal elements {e.g., Bi 0.925 La 0.05 A 0.025 FeO 3 , A: Sm, Yb, Ho, Y, Nd, Pr, Dy, Gd; Bi 0.925 La 0.05 Sm 0.025 Fe 0.95 M 0.05 O 3 , M: Sc, In, Al, Ga, Ni, Co} fabricated by the conventional solid-state method. The influences of site engineering (e.g., Bi site or Fe site) as well as the doped element types on their phase structure, microstructure, and electrical properties have been comparatively analyzed. The ions (e.g., A=Sm, Yb, Ho, and Y) substitution for Bi site is helpful to attain both a pure phase structure and a relatively good piezoelectricity (d 33 ≥40 pC/N) of BFO ceramics, while the ions substitutions for Fe site cannot suppress the formation of impurity phases and then result in the degraded electrical properties. Both XRD and backscattered electron images fully confirmed the existence of the impurity phases (Bi-rich and Fe-rich counterparts) in the ceramics doped by Ga. According to the related experiments, the piezoelectric properties of bismuth ferrite ceramics can be promoted by the site engineering as well as the optimization of the element types. This result will point out a way for us to promote the piezoelectric properties of bismuth ferrite ceramics through choosing both suitable doping elements and eliminating impurity phases.

Temperature dependent piezoelectric response and strain–electric-field hysteresis of rare-earth modified bismuth ferrite ceramics

“…To date, preparing RE-BFO ceramics has proven to be arduous and the synthesis method has a significant impact on the chemical homogeneity, phase composition and functional behavior 18 . As a result, the reported electrical properties of RE-BFO ceramics vary widely 5,9,[18][19][20][21][22][23][24][25][26] , and a limited number of studies demonstrate either apparent saturated switching strains 9,18 , saturated polarizations 25,26 or high depoling temperatures [26][27][28] . Therefore, further investigation is still required in order to characterize and understand the electromechanical properties and high-temperature functionality of RE-BFO ceramics.…”

Blue or red photoluminescence emission in α‐Bi2O3 needles: Effect of synthesis method

“…Because of these properties, Bi 2 O 3 has become an important material for several applications, e.g. fuel cells, photocatalysts, gas sensors, multiferroics, and electronic components …”

MOCVD Growth of Perovskite Multiferroic BiFeO3 Films: The Effect of Doping at the A and/or B Sites on the Structural, Morphological and Ferroelectric Properties

“…Among the various methods, ion substitution is the most useful and widely applied method to improve the multiferroic properties of BiFeO 3. In particular, a lot of attention has been dedicated on doping of various elements like rare‐earth, alkaline‐earth metals and transition metals at the A or B site of bismuth ferrite to improve its magnetoelectric properties …”