Excess ZnO Addition in Pure and La‐Doped PZN–PZT Ceramics

Abstract

The effects of excess ZnO addition on phase structure, dielectric and piezoelectric properties in pure and La-doped lead zinc nicobate (PZN)-lead zirconate titanate (PZT) systems have been investigated. Addition of excess ZnO helps suppress and prevents the formation of pyrochlore phase for both systems. However, the effects on electrical properties in the systems were very different, even opposite. For the PZN-PZT system, excess ions possibly exist as second-phase inclusion particles. Based on Raman spectra and the changes in properties, in the La-doped PZN-PZT system, excess ions are very likely to enter A-site lead vacancies. Adding proper excess ZnO in La-like-doped PZN-based systems is an effective approach to achieve a pure perovskite phase, enhanced piezoelectric constant d 33 , and reduced dielectric loss.

Effect of ZnO whisker content on sinterability and fracture behaviour of PZT peizoelectric composites

“…doi:10.1016/j.jallcom.2010.05.067 met different degrees of success. Furthermore, the doping effect of ZnO powder in piezoelectrics can result in lower sintering temperature and improving electric properties [50][51][52][53][54] and the PZT/ZnO actuator sensitive to reducing gases was fabricated [55].…”

Investigation of La-doped 0.25Pb(Zn1/3Nb2/3)O3-0.75Pb(ZrxTi1-x)O3 ceramics near morphotropic phase boundary

“…Weston et al [19] considered that the tetragonal phase has lower dielectric loss than the rhombohedral phase because of a decrease in the mobility of the domain walls. It is noteworthy that the dielectric losses of 0.25PZN-0.75PLZT ceramics are relative low compared with 0.3PZN-0.7PLZT ceramics reported [8,10,20]. That implies some 0.25PZN-0.75PLZT ceramics which have good piezoelectric properties may be good candidates for device applications.…”

“…Low dielectric loss (tgδ00.2%) and high mechanical quality factor (Qm01041) were achieved through MnO 2 addition [6]. On the contrary, 0.3PZN-0.7PZT system is modified as "soft" piezoelectric ceramics just because of its higher piezoelectric properties, just like La-doped 0.3PZN-0.7PZT by Guochu Deng , Xia Zeng et al [8][9][10]. Though very high piezoelectric coefficient (d 33 0 845 pC/N) and electromechanical coupling factor (k p 00.7) were attained through a two-step hot-pressing route , dielectric loss is still high (tgδ>2.0%) and the cost is huge [8].…”

“…Though very high piezoelectric coefficient (d 33 0 845 pC/N) and electromechanical coupling factor (k p 00.7) were attained through a two-step hot-pressing route , dielectric loss is still high (tgδ>2.0%) and the cost is huge [8]. The good piezoelectric properties (d 33 0580±10 pC/N) was obtained by a conventional oxide mixing oxide technique and excess ZnO addition , but dielectric loss is higher (tgδ0 3.85%) [10]. So 0.25PZN-0.75PZT may be a good attempt to get optimal piezoelectric properties and low dielectric loss by La doping, though it was modified by MnO 2 doping [11] as "hard" piezoelectric ceramics.…”

Opto-electrical Behavior of Pb(Zn1/3Nb2/3)O3–Pb0.97La0.03(Zr,Ti)O3 Transparent Ceramics with Varying Defect Structure

“…However, this method is still challenging for PZN-based ceramic systems; and PZN ceramics synthesized using these processes are opaque. Although pure PZT is opaque, lanthanum doping on the A-site has been shown to impart transparency (Zeng et al 2005a(Zeng et al , 2005b(Zeng et al , 2006(Zeng et al , 2007Shannon, 1976;Etin et al 2007). Hence, La incorporation in PZN-PZT ceramics has been an effective method to induce transparency and at the same time improve the dielectric, piezoelectric and opto-electric properties of compositions near the MPB.…”