[1] [1] RDEL J, JO W, SEIFERT K T P, et al. Perspective on the development of lead-free piezoceramics［J］. J Am Ceram Soc, 2010, 92(6): 1153-1177.

[3] [3] SAITO Y, TAKAO H, TANI T, et al. Lead-free piezoceramics［J］. Nature, 2004, 432(7013): 84-87.

[4] [4] SAFARI A, ABAZARI M, KERMAN K, et al. (K0.44, Na0.52, Li0.04) (Nb0.84, Ta0.10, Sb0.06)O3 ferroelectric ceramics.［J］. IEEE T Ultrason Ferr, 2009, 56(8): 1586-1594.

[5] [5] HAGH N M, KERMAN K, JADIDIAN B, et al. Dielectric and piezoelectric properties of Cu2+-doped alkali niobates［J］. J Eur Ceram Soc, 2009, 29(11): 2325-2332.

[8] [8] LIN D, LI Z, ZHANG S, et al. Influence of MnO2 doping on the dielectric and piezoelectric properties and the domain structure in (K0.5Na0.5)NbO3 single crystals［J］. J Am Ceram Soc, 2010, 93(4): 941-944.

[9] [9] LIU Y, XU G, LIU J, et al. Dielectric, piezoelectric properties of MnO2-doped (K0.5Na0.5)NbO3-LiNbO3 crystal grown by flux- bridgman method［J］. J Alloys Compd, 2014, 603: 95-99.

[10] [10] INAGAKI Y, KAKIMOTO K, KAGOMIYA I. Ferroelectric domain structure of Na0.5K0.5NbO3 crystal grown by floating zone method［J］. Jpn J Appl Phys, 2009, 48(9S1): 09KC09.

[11] [11] LI X, CHEN C, DENG H, et al. The growth and properties of lead-free ferroelectric single crystals［J］. Crystals, 2015, 5(2): 172-192.

[13] [13] HUO X, ZHENG L, ZHANG S, et al. Growth and properties of Li, Ta modified (K, Na)NbO3 lead-free piezoelectric single crystals［J］. Phys Status Solidi(RRL), 2014, 8(1): 86-90.

[15] [15] FISHER J G, BEN?AN A, HOLC J, et al. Growth of potassium sodium niobate single crystals by solid state crystal growth[J]. J Cryst Growth,2007, 303(2): 487–492.

[16] [16] YANG J, YANG Q, LI Y, et al. Growth mechanism and enhanced electrical properties of K0.5Na0.5NbO3-based lead-free piezoelectric single crystals grown by a solid-state crystal growth method［J］. J Eur Ceram Soc, 2016, 36(3): 541-550.

[17] [17] JIANG M, RANDALL C A, GUO H, et al. Seed-free solid-state growth of large lead-free piezoelectric single crystals: (Na1/2K1/2)NbO3［J］. J Am Ceram Soc, 2015, 98(10): 2988-2996.

[18] [18] SARAVANAN R, RAJESH D, RAJASEKARAN S V, et al. Effect of Ta doped on microstructure of sodium potassium niobate single crystal grown by flux method［J］. AIP Conf Proc, 2013, 1536(1): 863-864.

[19] [19] WANG K, LI J F. Domain engineering of lead-free Li-modified (K, Na)NbO3 polycrystals with highly enhanced piezoelectricity［J］. Adv Funct Mater, 2010, 20(12): 1924-1929.

[20] [20] PENG X, ZHANG B, ZHU L, et al. Multi-phase structure and electrical properties of Bi0.5Li0.5ZrO3 doping K0.48Na0.56NbO3 lead-free piezoelectric ceramics［J］. J Adv Ceram, 2018, 7(1): 79-87.

[22] [22] LV X, WU J, ZHU J, et al. Enhanced temperature stability in the R-T phase boundary with dominating intrinsic contribution［J］. Phys Chem Chem Phys, 2018, 20(30): 20149-20159.

[23] [23] SHALINI K, GIRIDHARAN N V. Observation of room temperature ferromagnetism and magneto-electric coupling in dual transition element substituted ferroelectric potassium sodium niobate- sciencedirect［J］. Ceram Int, 2019, 45(15): 19002-19014.