Structural transition and giant strain induced by A- and B-site concurrent donor doping in Bi0.5(Na0.84K0.16)0.5TiO3–SrTiO3 ceramics

Temperature‐Insensitive High Strain in Lead‐Free Bi0.5(Na0.84K0.16)0.5TiO3–0.04SrTiO3 Ceramics for Actuator Applications

“…For unmodified BNKT–ST ceramic S max / E max ~180 pm/V, and increased to a maximum value of ~800 pm/V for 2 mol% LN contents. This value is significantly higher than the previously reported BNT‐based nontextured ceramics . The origin of large strain in BNT‐based systems has been intensively studied.…”

“…These results indicate that the crystal structure of LN codoped BNKT–ST ceramics experienced a phase transformation, from the co‐existing rhombohedral and tetragonal phases into a pseudocubic phase. Such a phase transition has been observed in previously studied BNT–BKT solid solutions …”

“…Previously, most of the studies focused on the single A‐site or B‐site ion replacement in BNT‐based perovskite structures, with minimal interest in the effects of simultaneous A‐ and B‐site ion substitutions . Donor (referred to as “soft” dopant) doping generally leads to a destabilization of the ferroelectric (FE) order accompanied by an increase in the dielectric constants, piezoelectric constants, and electromechanical coupling coefficients, as well as a decrease in the Curie temperature and coercive field.…”

Evolution of phase structure and giant strain at low driving fields in Bi-based lead-free incipient piezoelectrics

“…Several researchers have attempted to lower this E th and improve the electric field-induced strain (EFIS) response [17][18][19][20][21][22][28][29][30][31][32][33][34][35][36]. Doping of impurities, either on the A-or Bsites of the ABO 3 perovskite structure, has been found as an effective method to enhance EFIS [19,[25][26][27][28].…”

Giant strain in lead-free relaxor/ferroelectric piezocomposite ceramics

“…A number of previous studies have reported that the electromechanical properties can be improved by modification of the MPB in BNKT with various dopants or modifiers [9]: BNKT−BiAlO 3 [10], BNKT−LiSbO 3 [11], and BNKT−BaTiO 3 [12] for their excellent ferroelectric and piezoelectric properties; Nb-doped BNKT [13,14], BNKT−Bi(Mg,Sn)O 3 [15], Liand Ta-codoped BNKT [16], BNKT−LaFeO 3 [17], Sndoped BNKT [18,19], BNKT−Ba 1/2 Ca 1/2 ZrO 3 [20], Ladoped BNKT [21][22][23], BNKT−(K,Na)NbO 3 [24], Nbdoped BNKT−SrTiO 3 [25], and BNKT−SrTiO 3 [26] for their giant electric-field-induced strain (EFIS) properties; BNKT−(K,Na)NbO 3 [27] and BNKT−BaZrO 3 [28] for their temperature-insensitive electrostrictive coefficient.…”