Effects of MnO2-doping on growth, structure and electrical properties of lead-free piezoelectric K0.5Na0.5NbO3-BiAlO3 single crystals

Structure and electrical properties of Cu, Bi and Mn co-doped K0.5Na0.5NbO3 single crystals grown by the seed-free solid state crystal growth method

“…Potassium sodium niobate (KNN)-based piezoelectric materials are considered to be one of the most likely systems to replace lead-containing piezoelectric materials owing to their excellent piezoelectric properties, environmental friendliness, high Curie temperature, mechanical quality factors, etc. [4][5][6][7][8][9][10][11][12][13] Piezoelectric single crystals and ceramics are common piezoelectric materials, but in the same composition, piezoelectric single crystals generally exhibit higher piezoelectric properties than ceramics made of polycrystalline particles. For example, the piezoelectric coefficient (d 33 ) of normal Na 0.5 Bi 0.5 TiO 3 -BaTiO 3 ceramics is about 100-150 pC N −1 , 14,15 but Na 0.5 Bi 0.5 TiO 3 -BaTiO 3 single crystals show a higher piezoelectric coefficient.…”

“…By this SFSSCG method, Jiang et al have successfully prepared a series of bulk KNN-based single crystals. [5][6][7][8][9][10][11][12] Subsequently, Yang 28 and Ahn 3 et al also obtained KNN-based crystals by the similar method.…”

“…Currently, KNN-based crystals grown by the SFSSCG method still have some problems, such as non-sufficient size, relatively high dielectric loss, numerous microdefects, etc. Based on our previous exploration of the SFSSCG method, the addition of trace Bi elements plays an important role in the growth of KNN single crystals, [5][6][7][8][9][10][11][12][13] but the existence of Bi may also be one of the main reasons for high dielectric loss and numerous microdefects in the crystals. Research studies show that doping is an effective way to improve the electrical properties of the KNN system.…”

“…Wang et al reported that introduction of Mn in Bi-containing KNN-based crystals enhanced their electrical properties. 5 Usually, CuO doping has been also used to reduce the dielectric loss of KNN-based ceramics while improving their mechanical quality factor. 30,31 Shen et al found that compared with pure LT-KNN ceramics (Q m = 69), the Q m of LT-KNN + 1 mol% CuO ceramics was increased by nearly five times (Q m = 323).…”

Comparison of (K0.5Na0.5)NbO3 Single Crystals Grown by Seed-Free and Seeded Solid-State Single Crystal Growth

“…These abnormal grains grow and consume all the matrix grains in the sample, forming single crystals. Single crystals of centimetre size have been grown with good piezoelectric properties in KNN and KNN-based systems [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. KNN-based single crystals grown by this method were successfully used to prepare an intravascular photoacoustic probe [ 52 ] and show potential for use as actuators [ 46 , 53 ].…”