fabrication of multilayered piezoceramic actuators. Certainly, other systems also have certain advantages, such as large piezoelectric strains in BNT‐based ceramics and high Curie temperature in BiFeO3‐based ceramics. However, all these known lead‐free materials are unlikely to be such an “all‐round player” that can be modified to exhibit different properties by changing doping elements as in PZT, so there still needs a further long way to develop lead‐free piezoceramics that are completely capable of replacing PZT‐based ceramics.
References
1 1 Gagliardi, M. (2019). Lead‐free piezoelectric ceramics market projected to grow at much faster pace through 2024. American Ceramic Society Bulletin 99: 7.
2 2 Jaffe, B., Cook, W.R., and Jaffe, H. (1971). Piezoelectric Ceramics. Academic Press.
3 3 Sawaguchi, E. (1953). Ferroelectricity versus antiferroelectricity in the solid solutions of PbZrO3 and PbTiO3. Journal of the Physical Society of Japan 8: 615–629.
4 4 Jaffe, B., Roth, R.S., and Marzullo, S. (1955). Properties of piezoelectric ceramics in the solid‐solutions series lead titanate–lead zirconate–lead oxide: tin oxide and lead titanate–lead hafnate. Journal of Research of the National Bureau of Standards 55: 239–254.
5 5 Noheda, B., Cox, D.E., Shirane, G. et al. (1999). A monoclinic ferroelectric phase in the Pb(Zr1−xTix)O3 solid solution. Applied Physics Letters 74: 2059–2061.
6 6 Noheda, B., Gonzalo, J.A., Cross, L.E. et al. (2000). Tetragonal‐to‐monoclinic phase transition in a ferroelectric perovskite: the structure of PbZr0.52Ti0.48O3. Physical Review B 61: 8687–8695.
7 7 Wang, H., Zhu, J., Lu, N. et al. (2006). Hierarchical micro‐/nanoscale domain structure in M‐C phase of (1−x)Pb(Mg1/3Nb2/3)O3−xPbTiO3 single crystal. Applied Physics Letters 89: 042908.
8 8 EU‐Directive 2002/95/EC (2003). Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (RoHS). Official Journal of the European Union 46 (L37): 19.
9 9 Roedel, J. and Li, J.‐F. (2018). Lead‐free piezoceramics: status and perspectives. MRS Bulletin 43: 576–580.
10 10 Saito, Y., Takao, H., Tani, T. et al. (2004). Lead‐free piezoceramics. Nature 432: 84–87.
11 11 Jona, F. and Shirane, G. (1962). Ferroelectric Crystals. Oxford, UK: Pergamon Press.
12 12 Merz, W.J. (1949). The electric and optical behavior of BaTiO3 single‐domain crystals. Physical Review 76: 1221–1225.
13 13 Acosta, M., Novak, N., Rojas, V. et al. (2017). BaTiO3‐based piezoelectrics: fundamentals, current status, and perspectives. Applied Physical Review 4: 041305.
14 14 Gao, J., Ke, X., Acosta, M. et al. (2018). High piezoelectricity by multiphase coexisting point: barium titanate derivatives. MRS Bulletin 43: 595–598.
15 15 Wada, S., Yako, K., Kakemoto, H. et al. (2005). Enhanced piezoelectric properties of barium titanate single crystals with different engineered‐domain sizes. Journal of Applied Physics 98: 014109.
16 16 Ren, X.B. (2004). Large electric‐field‐induced strain in ferroelectric crystals by point‐defect‐mediated reversible domain switching. Nature Materials 3: 91–94.
17 17 Karaki, T., Yan, K., Miyamoto, T., and Adachi, M. (2007). Lead‐free piezoelectric ceramics with large dielectric and piezoelectric constants manufactured from BaTiO3 nano‐powder. Japanese Journal of Applied Physics Part 2: Letters & Express Letters 46: L97–L98.
18 18 Shen, Z.‐Y. and Li, J.‐F. (2010). Enhancement of piezoelectric constant d33 in BaTiO3 ceramics due to nano‐domain structure. Journal of the Ceramic Society of Japan 118: 940–943.
19 19 Liu, W.F. and Ren, X.B. (2009). Large piezoelectric effect in Pb‐free ceramics. Physical Review Letters 103: 257602.
20 20 Kuroiwa, Y., Aoyagi, S., Sawada, A. et al. (2001). Evidence for Pb–O covalency in tetragonal PbTiO3. Physical Review Letters 87: 217601.
21 21 Shirane, G., Newnham, R., and Pepinsky, R. (1954). Dielectric properties and phase transitions of NaNbO3 and (Na,K)NbO3. Physical Review 96: 581–588.
22 22 Jaeger, R.E. and Egerton, L. (1962). Hot pressing of potassium–sodium niobates. Journal of the American Ceramic Society 45: 209–213.
23 23 Li, J.‐F., Wang, K., Zhu, F.‐Y. et al. (2013). (K,Na)NbO3‐based lead‐free piezoceramics: fundamental aspects, processing technologies and remaining challenges. Journal of the American Ceramic Society 96: 3677–3696.
24 24 Wu, J.G., Xiao, D.Q., and Zhu, J.G. (2015). Potassium–sodium niobate lead‐free piezoelectric materials: past, present, and future of phase boundaries. Chemical Reviews 115: 2559–2595.
25 25 Wang, K., Malic, B., and Wu, J.G. (2018). Shifting the phase boundary: potassium sodium niobate derivates. MRS Bulletin 43: 607–611.
26 26 Zhang, Y.C. and Li, J.‐F. (2019). Review of chemical modification on potassium sodium niobate lead‐free piezoelectrics. Journal of Materials Chemistry C 74: 284–4303.
27 27 Li, P., Zhai, J.W., Shen, B. et al. (2018). Ultrahigh piezoelectric properties in textured (K,Na)NbO3‐based lead‐free ceramics. Advanced Materials 30: 1705171.
28 28 Dai, Y.J., Zhang, X.W., and Zhou, G.Y. (2007). Phase transitional behavior in K0.5Na0.5NbO3–LiTaO3 ceramics. Applied Physics Letters 90: 262903.
29 29 Yao, F.‐Z., Wang, K., Jo, W. et al. (2016). Diffused phase transition boosts thermal stability of high‐performance lead‐free piezoelectrics. Advanced Functional Materials 26: 1217–1224.
30 30 Liu, Q., Li, J.‐F., Zhao, L. et al. (2018). Niobate‐based lead‐free piezoceramics: a diffused phase transition boundary leading to temperature‐insensitive high piezoelectric voltage coefficients. Journal of Materials Chemistry C 6: 1116–1125.
31 31 Liu, Q., Zhang, Y., Gao, J. et al. (2018). High‐performance lead‐free piezoelectrics with local structural heterogeneity. Energy & Environmental Science 11: 3531–3539.
32 32 Kawada, S., Kimura, M., Higuchi, Y., and Takagi, H. (2009). (K,Na)NbO3‐based multilayer piezoelectric ceramics with nickel inner electrodes. Applied Physics Express 2: 111401.
33 33 Smolenskii, G., Isupov, V., Agranovskaya, A., and Krainik, N. (1961). New ferroelectrics of complex composition. Soviet Physics – Solid State 2: 2651–2654.
34 34 Roleder, K., Franke, I., Glazer, A.M. et al. (2002). The piezoelectric effect in Na0.5Bi0.5TiO3 ceramics. Journal of Physics: Condensed Matter 14: 5399–5406.
35 35 Takenaka, T., Maruyama, K., and Sakata, K. (1991). (Bi1/2Na1/2)TiO3–BaTiO3 system for lead‐free piezoelectric ceramics. Japanese Journal of Applied Physics Part 1 30: 2236–2239.
36 36 Paterson, A.R., Nagata, H., Tan, X.L. et al. (2018). Relaxor‐ferroelectric transitions: sodium bismuth titanate derivatives. MRS Bulletin 43: 600–606.
37 37 Herabut, A. and Safari, A. (1997). Processing and electromechanical properties of (Bi0.5Na0.5)(1−1.5x)LaxTiO3 ceramics. Journal of the American Ceramic Society 80: 2954–2958.
38 38 Takenaka, T. and Nagata, H. (2005). Current status and prospects of lead‐free piezoelectric ceramics.
