本論文主要研究無鉛弛緩鐵電鈮酸鈉鉀基((Na, K)NbO3-based)陶瓷之開發與壓電揚聲器之應用。本論文主要分為三個部分:
第一部分為無鉛弛緩鐵電陶瓷之開發，利用Ba(Mg1/3Nb2/3)O3與SrTiO3來替換(Na, K)NbO3-based陶瓷中A位與B位離子，並使用經驗法則、居里魏斯定理和旋轉玻璃模型來探討其介電行為。研究結果顯示出，在(Na, K)NbO3陶瓷系統中加入 Ba(Mg1/3Nb2/3)O3的摻雜會增加模糊相變行為，且介電行為從長程有序鐵電特性被改變為短程有序的弛豫鐵電特性。因為離子替換後引起晶格結構改變、微觀結構改變、組成擾動、陽離子無序度增加和鄰近簇相關行為的變化。另外，在(Na, K)NbO3-SrTiO3陶瓷系統中增加SrTiO3摻雜量時，晶體結構從正交晶系轉變為四方晶系，然後出現偽立方對稱性，晶粒尺寸減小，介電弛豫行為變強，居里溫度轉移到較低的溫度。
第二部分為壓電特性的改良，使用(Na, K)NbO3陶瓷並加入鋰、鉭、銻與不同比例的SrTiO3合成（Na0.48-xK0.48-xLi0.04）Nb0.89-xTa0.05Sb0.06O3-xSrTiO3（NKLNTS-xST, x = 0, 0.003, 0.005, 0.007, 0.008, 0.01, 0.013和0.02），研究結果指出當SrTiO3摻雜的量增加時，相變溫度TO-T和Tc急劇降低，並且在當SrTiO3比例為0.005-0.008莫耳發現正交相和四方相的共存現象，導致電特性顯著增強。 當SrTiO3比例為 0.007莫耳的陶瓷具有良好的電特性能（d33 = 280 pC/N、kp = 47%, ɛ = 1666、g33 = 19×10-3 Vm/N、d33×g33 = 5202×10-15 m2/N、Pr = 15.1 μC/cm2、Ec = 14.2 kV/cm)。此外使用經驗法則、居里魏斯定理和旋轉玻璃模型來探討其介電行為。根據擬合結果和實驗數據，隨著SrTiO3摻雜量的增加，由於陽離子的無序性增強介電性能表現出強烈的弛豫特性。
第三部分為積層陶瓷之開發並應用於壓電揚聲器，本文使用無鉛 （Na0.48-xK0.48-xLi0.04）Nb0.89-xTa0.05Sb0.06O3-xSrTiO3（NKLNTS-xST, x = 0和0.007）陶瓷及市售的鉛基陶瓷為材料，配合多層技術製備了三個壓電聲學揚聲器。並使用X-射線繞射分析和穿透式電子顯微鏡圖像探討了NKLNTS-xST陶瓷的晶相結構和晶域結構。依據實驗結果，用（Na0.473K0.473Li0.04Sr0.007）Nb0.883Ti0.007Ta0.05Sb0.06O3 (NKLNTS-0.007ST)製備的壓電片及壓電揚聲器具有最佳的d33值650 pC/N及最佳的聲壓位準(sound pressure level, SPL)。其物理上的反應機制，因為NKLNTS-0.007ST陶瓷存在正交相和四方相共存，導致奈米級的晶域增加，使壓電陶瓷振動幅度增大並提高聲壓位準。

In this thesis, lead-free relaxor ferroelectric (Na, K)NbO3-based (NKN-based) ceramics are prepared by using conventional oxide solid-state reaction method and multi-layer technology for piezoelectric acoustic actuators. Their electrical characteristics are detailedly investigated. This thesis is divided into three parts:
Firstly, lead-free relaxor ferroelectric ceramics (Na, K)NbO3 doped with Ba (Mg1/3Nb2/3)O3 and SrTiO3 are developed. In the (Na, K)NbO3-based ceramic systems, Ba (Mg1/3Nb2/3)O3 and SrTiO3 are used to substitute for the A and B-site ions. The dielectric behaviors are also investigated by using the empirical law, the Curie-Weiss law and the spin-glass model. It is found that the diffused phase transition behavior are enhanced and the dielectric behavior are changed to the more short range order relaxor ferroelectric by increasing Ba(Mg1/3Nb2/3)O3 additions for (Na, K)NbO3-based ceramics. The physical response mechanisms are suggested that Barium and Magnesium cations enter into the cation sites and induce the changes of lattice structure, microstructure, compositional fluctuation, cation disorder and correlation of neighboring cluster-size moments. In addition, the crystal structures are changed from orthorhombic to tetragonal and then pseudo-cubic symmetries, the grain sizes are decreased, the dielectric relaxor behaviors are enhanced, and the Curie temperature are shifted to a lower temperature when the amounts of SrTiO3 are increased for (Na, K)NbO3-based ceramics.
Secondly, the piezoelectric properties of (Na, K)NbO3 ceramics are improved by doping the additions of lithium, tantalum, antimony and different SrTiO3 content The nonstoichiometric (Na0.48-xK0.48-xLi0.04)Nb0.89-xTa0.05Sb0.06O3-xSrTiO3 (NKLNTS-xST, where x = 0, 0.003, 0.005, 0.007, 0.008, 0.01, 0.013, and 0.02) ceramic systems are synthesize. When the amounts of SrTiO3 dopants are increased, the phase transition temperatures TO–T and Tc are drastically decreased, and the phase coexistence of the orthorhombic and tetragonal phases are induced at the 0.005-0.008 mole doping concentration of SrTiO3. And then, the electric properties are significantly improved due to the phase coexistence. The ceramics with 0.007 mole doping concentration of SrTiO3 exhibit the best electrical properties, d33 = 280 pC/N, kp = 47%, ɛ = 1666, g33 = 19×10-3 Vm/N, d33×g33= 5202×10-15 m2/N, Pr = 15.1 μC/cm2, and Ec = 14.2 kV/cm. In addition, the dielectric behavior are also investigated by using the empirical law, the Curie-Weiss law and the spin-glass model. According to the fitting results and experimental data, the dielectric properties exhibit more relaxor ferroelectric properties with increasing the amounts of SrTiO3 dopants because the cation disorders are significantly enhanced.
Finally, three piezoelectric acoustic actuators are fabricated by multi-layer technology by using lead-free (Na0.48-xK0.48-xLi0.04)Nb0.89-xTa0.05Sb0.06O3-xSrTiO3 (NKLNTS-xST) ceramics, x = 0 and 0.007, and commercial lead-based ceramics. The phase and domain structures are also investigated by using the XRD patterns and TEM images for the NKLNTS-xST ceramics. The (Na0.473K0.473Li0.04Sr0.007)Nb0.883Ti0.007Ta0.05Sb0.06O3 piezoelectric acoustic actuator has the best sound pressure level and d33 value of 650 pC/N. The response mechanisms suggest that the piezoelectric ceramic vibration amplitude is increased and the sound pressure level is also improved since the orthorhombic and tetragonal phases are coexistent and the nanoscale domains are increased for the (Na0.473K0.473Li0.04Sr0.007)Nb0.883Ti0.007Ta0.05Sb0.06O3 ceramics.

[1] H. J. Kim, K. Koo, S. Q. Lee, K. H. Park, and J. Kim, “High Performance Piezoelectric Microspeakers and Thin Speaker Array System,” ETRI J., 31, 680-687 (2009)
[2] K. Uchino, “Piezoelectric actuator and ultrasonic motors,” Kluwer Academic Publisher; Massachusetts (1996).
[3] Y. Zhuang, S. O. Ural, R. Gosain, S. Tuncdemir, A. Amin, and K. Uchino, “High Power Piezoelectric Transformers with Pb(Mg1/3Nb2/3)O3–PbTiO3 Single Crystals,” Appl. Phys. Express., 2, 121402 (2009).
[4] D. Pan, F. Dai, and H. Li “Piezoelectric energy harvester based on bi-stable hybrid symmetric laminate,” Compos. Sci. Technol., 119, 34-45 (2015).
[5] E. Sun., and W. Cao, “Relaxor-based ferroelectric single crystals growth, domain engineering, characterization and applications,” Prog. Mater. Sci., 65, 124–210 (2014).
[6] M. Kondo, M. Hida, M. Tsukada, K. Kurihara, and N. Kamehara, “Piezoelectric properties of Pb(Ni1/3,Nb2/3)O3–PbTiO3–PbZrO3 ceramics,” Jpn. J. Appl. Phys., 36, 6043-6045 (1997).
[7] Y. Guo, K. Kakimoto, and H. Ohsato, “Dielectric and piezoelectric properties of lead-free (Na0.5K0.5)NbO3–SrTiO3 ceramics,” Solid State Commun., 129, 279-284 (2004).
[8] G. H. Haertling, “Properties of hot-pressed ferroelectric alkali niobate ceramics,” J. Am. Ceram. Soc.. 50, 329-330 (1967).
[9] R. Wang, R. Xie, T. Sekiya, Y. Shimojo, Y. Akimune, N. Hirosaki, and M. Itoh, “Piezoelectric properties of spark-plasma-sintered (Na0.5K0.5)NbO3–PbTiO3 ceramics,” Jpn. J. Appl. Phys., 41, 7119-7122 (2002).
[10] S. H. Lee and Y. H. Lee, “Electrical properties of (Na,K)NbO3-BaTiO3 ceramics fabricated by a physicochemical method,” J. Ceram. Process. Res., 12, 416-419 (2011).
[11] R. Zuo, X. Fang, and C. Ye, “Enhanced dielectric and piezoelectric properties in LiTaO3-doped lead-free (K, Na)NbO3 ceramics by optimizing sintering temperature,” Appl. Phys. Lett., 90, 092904 (2007).
[12] R. Zuo, X. Fang, C. Ye, and L. Li, “Phase transitional behavior and piezoelectric properties of lead-free (Na0.5K0.5)NbO3–(Bi0.5K0.5)TiO3 ceramics,” J. Am. Ceram. Soc., 90, 2424–2428 (2007).
[13] S. Zhang, R. Xia, T. R. Shrout, G. Zang, and J.Wang, “Characterization of lead free (K0.5Na0.5)NbO3–LiSbO3 piezoceramic,” Solid State Commun., 141, 675-679 (2007).
[14] H. C. Song, K. H. Cho, H. Y. Park, C. W. Ahn, S. Nahm, K. Uchino, S. H. Park, and H. G. Lee, “Microstructure and piezoelectric properties of (1−x)(Na0.5K0.5)NbO3–xLiNbO3 ceramics,” J. Am. Ceram. Soc., 90, 1812–1816 (2007).
[15] P. Zhao, B. P. Zhang, and J. F. Li, “Enhanced dielectric and piezoelectric properties in LiTaO3-doped lead-free (K, Na)NbO3 ceramics by optimizing sintering temperature,” Scr. Mater., 58, 429-432 (2008).
[16] J. F. Li, K. Wang, F. Y. Zhu, L. Q. Cheng, F. Z. Yao, and D. J. Green, “(K, Na)NbO3-Based Lead-Free piezoceramics: fundamental aspects, processing technologies, and remaining challenges,” J. Am. Ceram. Soc., 96, 3677–3696 (2013).
[17] W. Feng, H. Du, C. Chen, Y. Huang, and X. Tan, “Electric-Field-Driven Phase Transition Process in (K, Na, Li)(Nb, Ta, Sb)O3 Lead-Free Piezoceramics,” J. Am. Ceram. Soc., 99, 135-140 (2016).
[18] X. Zhao, B. Zhang, L. Zhu, L. Zhao, and P. Zhou, “Study of polymorphic phase boundary in (Na, K, Li) (Nb, Ta, Sb)O3 piezoelectric ceramics,” J. Phys. D: Appl. Phys., 47, 065105 (2014).
[19] X. Pang, J. Qiu, K. Zhu, and B. Shao, “Influence of sintering temperature on piezoelectric properties of (K0.4425Na0.52Li0.0375)(Nb0.8925Sb0.07Ta0.0375)O3 lead-free piezoelectric ceramics,” J. Mater. Sci.-Mater. Electron., 22, 1783-1787 (2011).
[20] J. Du, X. J. Yi, C. L. Ban, Z. J. Xu, P. P. Zhao, and C. M. Wang, “Piezoelectric properties and time stability of lead-free (Na0.52K0.44Li0.04)Nb1−x−ySbxTayO3 ceramics,” Ceram. Int., 39, 2135-2139 (2013).
[21] S. Qian, K. Zhu, X. Pang, J. Liu, J. Qiu, and J. Du, “Phase transition, microstructure, and dielectric properties of Li/Ta/Sb co-doped (K, Na)NbO3 lead-free ceramics,” Ceram. Int., 40, 4389- 4394 (2014).
[22] L. Zheng, J.Wang, B. Ming, C.Wang, J. Du, and Q.Wu, “Phase structure and electrical properties of strontium modified (Na0.48–xK0.48–xLi0.04Srx)Nb0.89Ta0.05Sb0.06O3 ceramics,” Phys. Status. Solidi. A, 206, 1602-1605 (2009).
[23] R. C. Chang, S. Y. Chu, Y. P. Wong, C. S. Hong, and H. H. Huang, “The effects of sintering temperature on the properties of lead-free (Na0.5K0.5)NbO3–SrTiO3 ceramics,” J. Alloy. Compd., 456, 308-312 (2008).
[24] Y. Guo, K. Kakimoto, and H. Ohsato, “Dielectric and piezoelectric properties of lead-free (Na0.5K0.5)NbO3–SrTiO3 ceramics,” Solid State Commun., 129, 279-284 (2004).
[25] H. J. Kim, W. S. Yang, and K. No, “Improvement of low-frequency characteristics of piezoelectric speakers based on acoustic diaphragms,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 59, 2027-2035 (2012).
[26] W. G. Cady, “Piezoelectricity,” McGraw-Hill, New York (1946).
[27] K. Uchino, “Ferroelectric Devices,” Marcel Dekker, Inc. New York (2000).
[28] V. M. Goldschmidt, “Die Gesetze der Krystallochemie,” Naturwissenschaften, 14, 477-485 (1926).
[29] P. Baettig, C. F. Schelle, R. Lesar, U. V. Waghmare, and N. A. Spaldin, “Theoretical prediction of new high-performance lead-free piezoelectrics,” Chem. Mater., 17, 1376-1380 (2005).
[30] W. Pan, G. O. Dayton, and L. E. Cross, “dielectric aging effects in doped lead magnesium niobate: leadtitanate relaxor ferroelectric ceramics,” J. Mater. Sci. Lett., 5, 645-647 (1986).
[31] M. Y. Chen, C. T. Chia, I. N. Lin, L. J. Lin, C. W. Ahn, and S. Nahm, “Microwave properties of Ba(Mg1/3Ta2/3)O3, Ba(Mg1/3Nb2/3)O3 and Ba(Co1/3Nb2/3)O3 ceramics revealed by Raman scattering,” J. Eur. Ceram. Soc., 26, 1965-1968 (2006).
[32] S. G. JUN, and N. K. KIM, “Dielectric properties of PFW-PMN relaxor system prepared by B-site precursor method,” J. Mater. Sci., 35, 2093– 2097 (2000).
[33] W. Kanzig, “Ferroelectrics and antiferroelectrics,” Academic Press, (1957).
[34] C. C. Tsai, “Development of low-temperature-sintering synthesis technique of piezoceramics with high mechanical quality factor, design and fabrication of high-power therapeutic transducers,” Ph. Dissertation, Department of Electronic Engineering, Southern Taiwan University, Tainan, Taiwan, R.O.C (2011).
[35] D. W. Dye, “The piezo-electric quartz resonator and its equivalent electrical circuit,” Proc. Phys. Soc., London, 38, 399-458 (1926).
[36] S. Butterworth, “On electrically-maintained vibrations,” Proc. Phys. Soc., London, 27, 410-424 (1915).
[37] IEEE standard on piezoelectricity, New York, 176, 42 (1978)
[38] K. Uchino, “Ferroelectric devices,” Marcel Dekker, Inc., New York 3 (2003).
[39] K. Othmon, “ferroelectrics,” Encyclopedia of Chemical Technology 3rd ed., v 10.
[40] D. Sherrington and S. Kirkpatrick, “Solvable Model of a Spin-Glass,” Phys. Rev. Lett., 35, 1792-1795 (1975).
[41] D. Viehland, S. J. Jang, L. E. Cross, and M. Wuttig, “Deviation from Curie-Weiss behavior in relaxor ferroelectrics,” Phys. Rev. B., 46, 8003-8006 (1992).
[42] S. A. Gridnev, A. A. Glazunov, andA. N. Tsotsorin, “Temperature evolution of the local order parameter in relaxor ferroelectrics (1–x)PMN–xPZT,” Phys. Status Solidi A-Appl. Mat., 202, R122-R124 (2005).
[43] G. Burns and F. H. Dacol, “Glassy polarization behavior in ferroelectric compounds Pb(Mgl/3Nb2/3)O3 and Pb(Znl/3Nb2/3)O3,” Solid State Commun., 48, 853-856 (1983).
[44] D. Viehland, S. J. Jang, L. E. Cross, and M. Wuttig, “Deviation from Curie-Weiss behavior in relaxor ferroelectrics,” Phys. Rev. B., 46, 8003-8006 (1992).
[45] G. Burns and F. H. Dacol, “Crystalline ferroelectrics with glassy polarization behavior ,” Phys. Rev. B., 28, 2527-2530 (1983).
[46] D. Sherrington, and S. Kirkpatrick, Solvable Model of a Spin-Glass, Phys. Rev. Lett., 35, 1792-1796 (1975).
[47] L. P. Curecheriu, A. Ianculescu, and L. Mitoseriu, “Tunability properties in the paraelectric state of the Pb(Mg1/3Nb2/3)O3 ceramics,” J. Eur. Ceram. Soc., 30, 599-603 (2010).
[48] G. A. Smolenskii, “Physical phenomena in ferroelectrics with diffused phase transition,” J. Phys. Soc. Jpn. Suppl., 28, 26-37 (1970).
[49] I. A. Santos and J. A. Eiras, “Phenomenological description of the diffuse phase transition in ferroelectrics,” J. Phys.-Condes. Matter., 13, 11733 (2001).
[50] C. S. Hong, S. Y. Chu,W. C. Su, R. C. Chang, H. H. Nien, and Y. D. Juang, “he dependence of the synthesis condition on the dielectric behaviors of the 0.75Pb(Fe2/3W1/3)O3–0.25PbTiO3 based ceramics,” J. Alloys Compd., 459, 328-332 (2008).
[51] C. S. Hong, S. Y. Chu,W. C. Su, R. C. Chang, H. H. Nien, and Y. D. Juang, “Investigation of the dielectric properties of MnO-additive Pb(Fe2/3W1/3)–PbTiO3 relaxors prepared by two different methods,” J. Alloys Compd., 460, 658-667 (2008).
[52] C. S. Hong, S. Y. Chu, and C. C. Hsu, “Effects of the sintering temperature on the diffused phase transition and the spin-glassy behavior in Pb0.95La0.05(Fe2/3W1/3)0.65Ti0.35O3 ceramics,” J. Appl. Phys., 107, 094110 (2010).
[53] C. S. Hong, S. Y. Chu, C. C. Tsai, C. C. Hsu, and H. H. Su, “ Effects of lanthanum dopants on the Curie–Weiss and the local order behaviors for Pb1−xLax(Fe2/3W1/3)0.7Ti0.3O3 relaxor ferroelectrics,” Mater. Res. Bull., 48, 200 (2013).
[54] H. J. Kim, W. S. Yang, and K. S. No, “The vibrational characteristics of the triple-layered multimorph ceramics for high performance piezoelectric acoustic actuators,” J. Electroceram, 33, 53–63 (2014).
[55] H. J. Kim, W. S. Yang, and K. S. No, “Improvement of low-frequency characteristics of piezoelectric speakers based on acoustic diaphragms,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control., 59, 2027-2035 (2012).
[56] S. G. JUN, and N. K. KIM, “Dielectric properties of PFW-PMN relaxor system prepared by B-site precursor method,” J. Mater. Sci., 35, 2093– 2097 (2000).
[57] H. Uršič, M. Santo Zarnik, and M. Kosec, Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) Material for Actuator Applications, Smart Materials Research, 2011, 1-6 (2011).
[58] M. T. Lanagan, N. Yang, D. C. Dube, and S. J. Jang, “Dielectric Behavior of the Relaxor Pb(Mg1/3Nb2/3)O3—PbTiO3 Solid-Solution System in the Microwave Region,” J. Am. Ceram. Soc., 72, 481–483 (1989).
[59] A. Moquim, and M. R. Panigrahi, “Phase transition and relaxor nature of (Ba0.77Ca0.23)(Ti0.98La0.02)O3 ceramic prepared by mixed oxide route,” J. Mater. Sci.-Mater. Electron., 26, 4956-4962 (2015).
[60] L. Mitoseriu, A. Stancu, C. Fedor, and P. M. Vilarinho, “Analysis of the composition-induced transition from relaxor to ferroelectric state in PbFe2/3W1/3O3–PbTiO3 solid solutions,” J. Appl. Phys., 94, 1918-1925 (2003).
[61] L. Mitoseriu, P. M. Vilarinho, and J. L. Baptista, “Phase coexistence in Pb(Fe2/3W 1/3)O3–PbTiO3 solid solutions,” Appl. Phys. Lett., 80, 4422-4424 (2002).
[62] A. A. Bokov, Y. H. Bing, W. Chen, Z. G. Ye, S. A. Bogatina, I. P. Raevski, S. I. Raevskaya, and E. V. Sahkar, “Empirical scaling of the dielectric permittivity peak in relaxor ferroelectrics,” Phys. Rev. B, 68, 052102 (2003).
[63] Z. Y. Cheng, R. S. Katiyar, X. Yao, and A. S. Bhalla, “Temperature dependence of the dielectric constant of relaxor ferroelectrics,” Phys. Rev. B, 57, 8166-8177 (1998).
[64] L. Zhou, P. M. Vilarinho, and J. L. Baptista, “The characteristics of the diffuse phase transition in Mn doped Pb(Fe2/3W1/3)O3 relaxor ceramics,” J. Appl. Phys., 85, 2312-2317 (1999).
[65] R. M. V. Rao, A. Halliyal, and A. M. Umarji, “Perovskite Phase Formation in the Relaxor System [Pb(Fe1/2Nb1/2)O3]1-x–[Pb(Zn1/3Nb2/3)O3]x,” J. Am. Ceram. Soc., 79, 257-260 (1996).
[66] L. Zhou, P. M. Vilarinho, P. Q. Mantas, and J. L. Baptista, E. Fortunato, “The effects of La on the dielectric properties of lead iron tungstate Pb(Fe2/3W1/3)O3 relaxor ceramics,” J. Eur. Ceram. Soc., 20, 1035-1041 (2000).
[67] D. Szwagierczak, and J. Kulawik, “Influence of MnO2 and Co3O4 dopants on dielectric properties of Pb(Fe2/3W1/3)O3 ceramics,” J. Eur. Ceram. Soc., 25, 1657-1662 (2005).
[68] M. Adamczyk, Z. Ujma, L. Szymczak, and I. Gruszka, “Effect of Nb doping on the relaxor behaviour of (Pb0.75Ba0.25)(Zr0.70Ti0.30)O3 ceramics,” J. Eur. Ceram. Soc., 26, 331-336 (2006).
[69] M. Adamczyk, Z. Ujma, L. Szymczak, and J. Koperski, “Influence of post-sintering annealing on relaxor behaviour of (Pb0.75Ba0.25)(Zr0.70Ti0.30)O3 ceramics,” Ceram. Int., 31, 791-794 (2005).
[70] Y. Chang, Z. Yang, X. Chao, R. Zhang, X. Li, “Dielectric and piezoelectric properties of alkaline-earth titanate doped (K0.5Na0.5)NbO3 ceramics,” Mater. Lett., 61, 785-789 (2007).
[71] R. C. Chang, S. Y. Chu, Y. P. Wong, Y. F. Lin, and C. S. Hong, “Properties of (Na0.5K0.5)NbO3–SrTiO3 based lead-free ceramics and surface acoustic wave devices,” Sens. Actuator A-Phys., 136, 267-272 (2007).
[72] N. Jiang, B. Fang, Q. Du, and L. Zhou, “Effects of the Second Component on the Structure and Electrical Properties of Na1/2K1/2NbO3-Based Lead-Free Piezoelectric Ceramics,” Ferroelectrics, 413, 73-83 (2011).
[73] C. S. Chen, C. C. Chou, Y. S. Lin, P. Y. Chen, and H. Chen, “Effects of CaTiO3 addition on microstructures and electrical properties of Na0.52K0.48NbO3 lead-free piezoelectric ceramics,” Ceram. Int., 39, S125-S128 (2013).
[74] Y. Chang, Z. Yang, L. Wei, and B. Liu, “Effects of AETiO3 additions on phase structure, microstructure and electrical properties of (K0.5Na0.5)NbO3 ceramics,” Mater. Sci. Eng. A, 437, 301-305 (2006).
[75] A. Munpakdee, J. Tontragoon, K. Siriwitayakorn, and T. Tunkasiri, “Effects of Ba(Mg1/3Nb2/3)O3 on microstructure and dielectric properties of barium titanate ceramics,” J. Mater. Sci. Lett., 22, 1307– 1310 (2003).
[76] H. H. Su, C. S. Hong, C. C. Tsai, and S. Y. Chu, “Dielectric behaviors of Ba(Mg1/3Nb2/3)O3 modified (Na0.5K0.5)NbO3 ceramics” Ceram. Int., 44, 7955–7962 (2018).
[77] H. H. Su, C. S. Hong, C. C. Tsai, and S. Y. Chu, “Relaxor behavior of lead-free nonstoichiometric (Na0.48-xK0.48-xLi0.04)Nb0.89-xTa0.05Sb0.06O3-xSrTiO3 ceramics,” ECS J. Solid State Sci. Technol., 6, N117-N121 (2017).
[78] X. Zhao, B. Zhang, L. Zhu, L. Zhao and P. Zhou, “Study of polymorphic phase boundary in (Na, K, Li) (Nb, Ta, Sb)O3 piezoelectric ceramics,” J. Phys. D: Appl. Phys., 47, 065105 (2014).
[79] J. Wu, T. Peng, Y. Wang, D. Xiao, J. Zhu, Y. Jin, J. Zhu, P. Yu, L. Wu, and Y. Jiang, “Phase Structure and Electrical Properties of (K0.48Na0.52)(Nb0.95Ta0.05)O3-LiSbO3 Lead-Free Piezoelectric Ceramics,” J. Am. Ceram. Soc., 91, 319–321 (2008)
[80] J. Fu, R. Zuo, Y. Wu, Z. Xu, and L. Li, “Phase Transition and Electrical Properties of Li-and Ta-Substituted (Na0.52K0.48)(Nb0.96Sb0.04)O3 Piezoelectric Ceramics,” J. Am. Ceram. Soc., 91, 3771–3773 (2008).
[81] Y. Q. Li, H. X. Liu, Z. H. Yao, J. Xu, Y. J. Cui, H. Hao, M .H. Cao, and Z. Y. Yu, “Characterization and Energy Storage Density of BaTiO3–Ba(Mg1/3Nb2/3)O3 Ceramics,” Mater. Sci. Forum., 654-656, 2045-2048 (2010).
[82] D. Lin, K. W. Kwok, and H. L.W. Chan, “Microstructure, phase transition, and electrical properties of (K0.5Na0.5)1–xLix(Nb1−yTay)O3 lead-free piezoelectric ceramics,” J. Appl. Phys., 102, 034102 (2007).
[83] B. Qu, H. Du, Z. Yang, and Q. Liu, “Large recoverable energy storage density and low sintering temperature in potassium-sodium niobate-based ceramics for multilayer pulsed power capacitors,” J. Am. Ceram. Soc., 100, 1517-1526 (2017).
[84] L. Jiang, Y. Li, J. Xing, J. Wu, Q. Chen, H. Liu, D. Xiao, and J. Zhu, “Phase structure and enhanced piezoelectric properties in (1-x)(K0.48Na0.52)(Nb0.95Sb0.05)O3–x(Bi0.5Na0.42Li0.08)0.9Sr0.1ZrO3 lead-free piezoelectric ceramics,” Ceram. Int., 43, 2100-2106 (2017).
[85] R. Huang, D. Yan, Y. Zhao, and H. Zhou, “The effect of B-site substitution on the structural evolution and electrical properties of lead-free (K,Na)NbO3 ceramics,” Ceram. Int., 43, 2927-2932 (2017).
[86] H. Du, W. Zhou, F. Luo, D. Zhu, S. Qu, and Z. Pei, “New Lead-Free Relaxor Ferroelectrics Derived from (K0.5Na0.5)NbO3 for High Temperature Applications,” Ferroelectrics, 401, 141-147 (2010).
[87] K. Wang, and J. F. Li, “Domain Engineering of Lead-Free Li-Modified (K,Na)NbO3 Polycrystals with Highly Enhanced Piezoelectricity,” Adv. Funct. Mater., 20, 1924-1929 (2010).
[88] M. I. Mendelson, “Average Grain Size in Polycrystalline Ceramics,” J. Am. Ceram. Soc., 52, 443–446 (2006).
[89] F. Weill, J. L. Rehspringer, P. Poix, C. Kipelen, and J. C. Bernier, “Crystallographic study of BaTiO3-BaM1/3N2/3O3 solid solutions (M = Co or Mg and N = Nb or Ta),” J. Mater. Sci., 27, 2316-2320 (1992).
[90] A. Munpakdee, K. Pengpat, J. Tontrakoon, T. Tunkasiri, “The study of dielectric diffuseness in the Ba(Mg1/3Nb2/3)O3-BaTiO3 ceramic system,” Smart Mater. Struct., 15, 1255-1259 (2006).
[91] K. i. Kakimoto, K. Akao, Y. Guo, and H. Ohsato, “Raman Scattering Study of Piezoelectric (Na0.5K0.5)NbO3-LiNbO3 Ceramics,” Jpn. J. Appl. Phys., 44, 7064-7067 (2005).
[92] Y. Chang, Z. Yang, D. Ma, Z. Liu, and Z. Wang, “Phase coexistence and high electrical properties in (KxNa0.96−xLi0.04)(Nb0.85Ta0.15)O3 piezoelectric ceramics,” J. Appl. Phys., 105, 054101 (2009).
[93] C. Y. Xu, P. X. Zhang, and L. Yan, “Blue shift of Raman peak from coated TiO2 nanoparticles,” J. Raman Spectrosc., 32, 862-865 (2001).
[94] I. A. Santos, and J. A. Eiras, “Phenomenological description of the diffuse phase transition in ferroelectrics,” J. Phys.-Condes. Matter, 13, 11733 (2001).
[95] L. Mitoseriu, A. Stancu, C. Fedor, and P. M. Vilarinho, “Analysis of the composition-induced transition from relaxor to ferroelectric state in PbFe2/3W1/3O3–PbTiO3 solid solutions,” J. Appl. Phys., 94, 1918-1925 (2003).
[96] N. Vittayakorn, G. Rujijanagul, X. Tan, M. A. Marquardt, and D. P. Cann, “The morphotropic phase boundary and dielectric properties of the xPb(Zr1∕2Ti1∕2)O3-(1−x)Pb(Ni1∕3Nb2∕3)O3 perovskite solid solution,” J. Appl. Phys., 96, 5103-5109 (2004).
[97] J. Hao, W. Bai, W. Li, J. Zhai, and C. Randall, “Correlation between the microstructure and electrical properties in high-performance (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoelectric ceramics,” J. Am. Ceram. Soc., 95, 1998-2006 (2012).
[98] D. Sherrington, and S. Kirkpatrick, “Solvable Model of a Spin-Glass,” Phys. Rev. Lett., 35, 1792-1796 (1975).
[99] G. Burns, and F. H. Dacol, “Glassy polarization behavior in ferroelectric compounds Pb(Mgl/3Nb2/3)O3 and Pb(Znl/3Nb2/3)O3,” Solid State Commun.,” 48, 853-856 (1983).
[100] D. Viehland, S. J. Jang, L. E. Cross, and M. Wuttig, “Deviation from Curie-Weiss behavior in relaxor ferroelectrics,” Phys. Rev. B, 46, 8003-8006 (1992).
[101] L. P. Curecheriu, A. Ianculescu, and L. Mitoseriu, “Tunability properties in the paraelectric state of the Pb(Mg1/3Nb2/3)O3 ceramics,” J. Eur. Ceram. Soc., 30, 599-603 (2010).
[102] S. A. Gridnev, A. A. Glazunov, and A. N. Tsotsorin, “Temperature evolution of the local order parameter in relaxor ferroelectrics (1-x)PMN-xPZT,” Phys. Status Solidi A, 202, R122-R124 (2005).
[103] V. Bobnar, J. Bernard, and M. Kosec, “Relaxorlike dielectric properties and history-dependent effects in the lead-free K0.5Na0.5NbO3–SrTiO3 ceramic system,” Appl. Phys. Lett., 85, 994-996 (2004).
[104] Y. Guo, K. i. Kakimoto, and H. Ohsato, “Dielectric and piezoelectric properties of lead-free (Na0.5K0.5)NbO3–SrTiO3 ceramics,” Solid State Commun., 129, 279-284 (2004).
[105] K. H. Cho, H. Y. Park, C. W. Ahn, S. Nahm, K. Uchino, S. H. Park, H. G. Lee, and H. J. Lee, “Microstructure and Piezoelectric Properties of 0.95(Na0.5K0.5)NbO3-0.05SrTiO3 Ceramics,” J. Am. Ceram. Soc., 90, 1946-1949 (2007).
[106] M. Połomska, B. Hilczer, M. Kosec, and B. Malič, “Raman Scattering Studies of Lead Free (1-x)K0.5Na0.5NbO3-xSrTiO3 Relaxors,” Ferroelectrics, 369, 149-156 (2008).
[107] R. C. Chang, S. Y. Chu, Y. P. Wong, C. S. Hong, and H. H. Huang, “The effects of sintering temperature on the properties of lead-free (Na0.5K0.5)NbO3–SrTiO3 ceramics,” J. Alloy. Compd., 456, 308-312 (2008).
[108] H. Fang, Z. Li, P. Ren, and G. Jiao, “Relaxor Ferroelectricity and Electrostrictive Behavior of KNN-ST ceramics,” Mater. Sci. Forum., 654, 1978-1981 (2010).
[109] K. i. Kakimoto, K. Akao, Y. Guo, H. Ohsato, “Raman Scattering Study of Piezoelectric (Na0.5K0.5)NbO3-LiNbO3 Ceramics,” Jpn. J. Appl. Phys., 44, 7064-7067 (2005).
[110] F. Rubio-Marcos, M. G. Navarro-Rojero, J. J. Romero, P. Marchet, and J. F. Fernandez, “Piezoceramics properties as a function of the structure in the system (K,Na,Li)(Nb,Ta,Sb)O3,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 56, 1835-1842 (2009).
[111] H. Zheng, G. D. C. Csete de Györgyfalva, R. Quimby, H. Bagshaw, R. Ubic, I. M. Reaney, and J. Yarwood, “Raman spectroscopy of B-site order–disorder in CaTiO3-based microwave ceramics,” J. Eur. Ceram. Soc., 23, 2653-2659 (2003).
[112] Y. Chang, Z. p. Yang, D. Ma, Z. Liu, Z. Wang, “Phase transitional behavior, microstructure, and electrical properties in Ta-modified [(K0.458Na0.542)0.96Li 0.04] NbO3 lead-free piezoelectric ceramics,” J. Appl. Phys., 104, 024109 (2008).
[113] L. Ramajo, M. Castro, F. Rubio-Marcos, J. Fernandez-Lozano, “Influence of MoO3 on electrical and microstructural properties of (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3,” J. Mater. Sci.-Mater. Electron., 24 (9) 3587-3593 (2013).
[114] Y. Guo, K.-i. Kakimoto, and H. Ohsato, “Ferroelectric-relaxor behavior of (Na0.5K0.5)NbO3-based ceramics,” J. Phys. Chem. Solids., 65, 1831-1835 (2004).
[115] H. Y. Park, C. W. Ahn, H. C. Song, J. H. Lee, S. Nahm, K. Uchino, H. G. Lee, and H. J. Lee, “Microstructure and piezoelectric properties of 0.95(Na0.5K0.5)NbO3–0.05BaTiO3 ceramics,” Appl. Phys. Lett., 89, 062906 (2006).
[116] S. Zhang, H. J. Lee, C. Ma, X. Tan, and A. Fetiera, “Sintering Effect on Microstructure and Properties of (K,Na)NbO3 Ceramics,” J. Am. Ceram. Soc., 94, 3659-3665 (2011).
[117] K. Uchino, and S. Nomura, “Critical exponents of the dielectric constants in diffused-phase-transition crystals,” Ferroelectrics, 44, 55-61 (1982).
[118] P. Mishra, Sonia, and P. Kumar, “Effect of sintering temperature on dielectric, piezoelectric and ferroelectric properties of BZT–BCT 50/50 ceramics,” J. Alloy. Compd., 545, 210-215 (2012).
[119] J. Hao, W. Bai, W. Li, J. Zhai, and C. Randall, “Correlation Between the Microstructure and Electrical Properties in High-Performance (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 Lead-Free Piezoelectric Ceramics,” J. Am. Ceram. Soc., 95, 1998-2006 (2012).
[120] H. H. Su, C. S. Hong, C. C. Tsai, and S. Y. Chu, “Electric properties of SrTiO3 modified (Na0.48K0.48Li0.04)Nb0.89Ta0.05Sb0.06O3 lead-free ceramics,” ECS J. Solid State Sci. Technol., 5 N67-N71 (2016).
[121] K. Wang and J. F. Li, “Domain Engineering of Lead-Free Li-Modified (K, Na)NbO3 Polycrystals with Highly Enhanced Piezoelectricity,” Adv. Funct. Mater., 20, 1924-1929 (2010).
[122] D. Lin, K. W. Kwok, K. H. Lam, and H. L. W. Chan, Structure and electrical properties of K0.5Na0.5NbO3–LiSbO3 lead-free piezoelectric ceramics,” J. Appl. Phys., 101, 074111 (2007).
[123] Y. Wang, Y. Lu, M. Wu, D. Wang, Y. Li, and Y. Wang, “Phase Structure and Enhanced Piezoelectric Properties of Lead-Free Ceramics (1−x)(K0.48Na0.52)NbO3–(x/5.15)K2.9Li1.95Nb5.15O15.3 with High Curie Temperature,” Int. J. Appl. Ceram. Technol., 9, 221-227 (2012).
[124] Y. Zhao, L. Wang, R. Huang, R. Liu, and H. Zhou, “The correlation between the microstructure and macroscopic properties of (K, Na, Li)(Nb, Ta)O3 ceramic via rare earth oxide doping,” Ceram. Int., 40, 2505-2510 (2014).
[125] K. Kakimoto, K. Akao, Y. Guo, and H. Ohsato, “Raman Scattering Study of Piezoelectric (Na0.5K0.5)NbO3-LiNbO3 Ceramics,” Jpn. J. Appl. Phys., 44, 7064-7067 (2005).
[126] R. Singh, K. Kambale, A. R. Kulkarni, and C. S. Harendranath, “Structure composition correlation in KNN–BT ceramics – An X-ray diffraction and Raman spectroscopic investigation, ” Mater. Chem. Phys., 138, 905-908 (2013).
[127] F. Rubio-Marcos, M. A. Ba˜nares, J. J. Romero, and J. F. Fernandez, “Correlation between the piezoelectric properties and the structure of lead-free KNN-modified ceramics, studied by Raman Spectroscopy,” J. Raman Spectrosc., 42, 639-643 (2011).
[128] H. H. Su, C. S. Hong, C. C. Tsai, S. Y. Chu, and C. S. Lin, “Effect of microstructure on the dielectric properties of (1−x)Na0.5K0.5NbO3–xSrTiO3 ceramics,” Ceram. Int., 42 17558-17564 (2016).
[129] J. Ha, J. Ryu, and H. Lee, “Substitution behavior of x(Na0.5K0.5)NbO3-(1-x)BaTiO3 ceramics for multilayer ceramic capacitors by a near edge x-ray absorption fine structure analysis,” Appl. Phys. Lett., 104, 262904 (2014).
[130] S. L. Yang, C. C. Tsai, Y. C. Liou, C. S. Hong, B. J. Li, and S. Y. Chu, “Investigation of CuO-Doped NKN Ceramics with High Mechanical Quality Factor Synthesized by a B-Site Oxide Precursor Method,” J. Am. Ceram. Soc., 95, 1011-1017 (2011).
[131] J. Wu, D. Xiao, Y. Wang, L. Wu, Y. Jiang, and J. Zhu, “K/Na ratio dependence of the electrical properties of [(KxNa1−x)0.95Li0.05](Nb0.95Ta0.05)O3 lead-free ceramics,” J. Am. Ceram. Soc., 91, 2385-2387 (2008).
[132] C. W. Ahn, J. J. Choi, J. Ryu, W. H. Yoon, B. D. Hahn, J. W. Kim, J. H. Choi, and D. S. Park, “Composition design rule for energy harvesting devices in piezoelectric perovskite ceramics,” Mater. Lett., 141, 323-326 (2015).
[133] H. J. Kim, W. S. Yang, and K. No, “Improvement of low-frequency characteristics of piezoelectric speakers based on acoustic diaphragms,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 59, 2027–2035 (2012).
[134] I. T. Seo, I. Y. Kang, Y. J. Cha, J. H. Choi, S. Nahm, T. H. Sung, and H.C. Jung, “Piezoelectric properties of CuO-added (Na0.5K0.5)NbO3 ceramic multilayers,” J. Eur. Ceram. Soc., 32, 1085–1090 (2012).
[135] R. Gao, X. Chu, Y. Huan, Y. Sun, J. Liu, X. Wang, and L. Li, “A study on (K, Na)NbO3 based multilayer piezoelectric ceramics micro speaker,” Smart Mater. Struct., 23, 105018 (2014).
[136] T. Dias, R. Monaragala, and M. Soleimani, “Acoustic response of a curved active PVDF paper fabric speaker for active noise control of automotive interior noise,” Meas. Sci. Technol., 18, 1521–1532 (2007).
[137] Y. Wang, J. Wu, D. Xiao, W. Wu, B. Zhang, L. Wu, and J. Zhu, “Microstructure and electrical properties of [(K0.50Na0.50)0.95−xLi0.05Agx](Nb0.95Ta0.05)O3 lead-free ceramics,” J. Am. Ceram. Soc., 91, 2772–2775 (2008).
[138] P. Kumar, and P. Palei, “Effect of sintering temperature on ferroelectric properties of 0.94(K0.5Na0.5)NbO3–0.06LNbO3 system,” Ceram. Int., 36, 1725–1729 (2010).
[139] K. Kumar, and B. Kumar, “Effect of Nb-doping on dielectric ferroelectric and conduction behaviour of lead free Bi0.5(Na0.5K0.5)0.5TiO3 ceramic,” Ceram. Int., 38, 1157–1165 (2012).
[140] J. Ma, X. Liu, and W. Li, “High piezoelectric coefficient and temperature stability of Ga2O3-doped (Ba0.99Ca0.01)(Zr0.02Ti0.98)O3 lead-free ceramics by low-temperature sintering,” J. Alloy. Compd., 581, 642–645 (2013).
[141] L. F. Zhu, B. P. Zhang, X. K. Zhao, L. Zhao, F. Z. Yao, X. X. Han, P. F. Zhou, and J. F. Li, “Phase transition and high piezoelectricity in (Ba,Ca)(Ti1−xSnx)O3 lead-free ceramics,” Appl. Phys. Lett., 103, 072905 (2013).
[142] K. Sasanuma, S. Tsukada, J. Kano, S. Kojima, R. Wang, K. Hanada, K. Matsusaki, and H. Bando, “Investigation on sielectric and piezoelectric properties of (1-x)(Na0.5K0.5)NbO3-xSrTiO3 ceramics,” Ferroelectrics, 348, 106–112 (2007)
[143] R. Zuo, J. Fu, D. Lv, Phase transformation and tunable piezoelectric properties of lead-free (Na0.52K0.48−xLix)(Nb1−x-ySbyTax)O3 system, J. Am. Ceram. Soc., 92, 283–285 (2009).
[144] Y. Huang, H. Du, W. Feng, H. Qin, and Q. Hu, “Influence of SrZrO3 addition on structural and electrical properties of (K0.45Na0.51Li0.04)(Nb0.90Ta0.04Sb0.06)O3 lead-free piezoelectric ceramics,” J. Alloy. Compd., 590, 435–439 (2014).
[145] X. Zhao, B. Zhang, L. Zhu, L. Zhao, and P. Zhou, “Study of polymorphic phase boundary in (Na, K, Li) (Nb,Ta, Sb)O3 piezoelectric ceramics,” J. Phys. D: Appl. Phys., 47, 065105 (2014).
[146] W. Feng, H. Du, C. Chen, Y. Huang, and X. Tan, “Electric-field-driven phase transition process in (K, Na, Li)(Nb, Ta, Sb)O3 lead-free piezoceramics,” J. Am. Ceram. Soc., 99, 135–140 (2016).
[147] K. Wang, and J. F. Li, “Domain engineering of lead-free Li-modified (K, Na)NbO3 polycrystals with highly enhanced piezoelectricity,” Adv. Funct. Mater., 20, 1924–1929 (2010).
[148] Y. Huan, X. Wang, L. Li, and J. Koruza, “Strong domain configuration dependence of the nonlinear dielectric response in (K, Na)NbO3-based ceramics,” Appl. Phys. Lett., 107, 202903 (2015).
[149] Y. Qin, J. Zhang, W. Yao, C. Lu, and S. Zhang, “Domain configuration and thermal stability of (K0.48Na0.52)(Nb0.96Sb0.04)O3-Bi0.50(Na0.82K0.18)0.50ZrO3 piezoceramics with high d33 coefficient,” ACS Appl. Mater. Interfaces, 8, 7257–7265 (2016).
[150] D. Damjanovic, “A morphotropic phase boundary system based on polarization rotation and polarization extension,” Appl. Phys. Lett., 97, 062906 (2010).
[151] F. Jian, Z. Ruzhong, X. Zhengkui, “High piezoelectric activity in (Na, K)NbO3 based lead-free piezoelectric ceramics: contribution of nanodomains,” Appl. Phys. Lett., 99, 062901 (2011).
[152] J. Gao, Y. Hao, S. Ren, T. Kimoto, M. Fang, H. Li, Y. Wang, L. Zhong, S. Li, and X. Ren, “Large piezoelectricity in Pb-free 0.96(K0.5Na0.5)0.95Li0.05Nb0.93Sb0.07O3−0.04BaZrO3 ceramic: a perspective from microstructure,” J. Appl. Phys., 117, 084106 (2015).
[153] F. Z. Yao, K. Wang, L. Q. Cheng, X. Zhang, W. Zhang, F. Zhu, nd J. F. Li, “Nanodomain engineered (K, Na)NbO3 lead-free piezoceramics: enhanced thermal and cycling reliabilities,” J. Am. Ceram. Soc., 98, 448–454 (2015).
[154] H. J. Kim, W. S. Yang, and K. No, “Effects of an elastic mass on frequency response characteristics of an ultra-thin piezoelectric micro-acoustic actuator,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 60, 1587–1594 (2013).