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. Journal of the European Ceramic Society 25: 2693–2700.
39 39 Ma, C., Guo, H.Z., Beckman, S.P., and Tan, X.L. (2012). Creation and destruction of morphotropic phase boundaries through electrical poling: a case study of lead‐free (Bi1/2Na1/2)TiO3–BaTiO3 piezoelectrics. Physical Review Letters 109: 107602.
40 40 Jo, W., Schaab, S., Sapper, E. et al. (2011). On the phase identity and its thermal evolution of lead free (Bi1/2Na1/2)TiO3–6 mol% BaTiO3. Journal of Applied Physics 110: 074106.
41 41 Sasaki, A., Chiba, T., Mamiya, Y., and Otsuki, E. (1999). Dielectric and piezoelectric properties of (Bi0.5Na0.5)TiO3–(Bi0.5K0.5)TiO3 systems. Japanese Journal of Applied Physics 38: 5564.
42 42 Gorfman, S., Glazer, A.M., Noguchi, Y. et al. (2012). Observation of a low‐symmetry phase in Na0.5Bi0.5TiO3 crystals by optical birefringence microscopy. Journal of Applied Crystallography 45: 444–452.
43 43 Zhang,