Piezoelectric Properties and Local Structure Analysis of (Na_0.5K_0.45Li_0.05)NbO₃ Solid Solutions by Malic Acid Complex Solution Method

Abstract

Na0.50K0.45Li0.05)NbO3 (NKLN) powder was synthesized by the malic acid complex solution method, and NKLN solid solutions were then fabricated at firing temperatures of 900−1050°C using a conventional solid-state reaction technique. The piezoelectric properties of the resulting materials were measured, and samples produced at 950°C were found to exhibit the maximum d33 and kp values of 151 pC/N and 32%, respectively. On the basis of a local structural analysis using high-energy X-ray diffraction, the distortion of NbO6 octahedra, which is the origin of the ferroelectric properties, also exhibited a maximum at 950°C. Thus, this is the optimal firing temperature for fabricating NKLN samples with excellent piezoelectric properties and the largest NbO6 octahedral distortion.

Piezoelectric Properties and Local Structure of (Na_0.50K_0.45Li_0.05)NbO₃－Ca(Zr_0.50Ti_0.50)O₃ Solid Solutions Produced by Malic Acid Complex Solution Method

“…Table  lists the firing temperature, piezoelectric properties and Curie temperature for NKLN CZT2, 0.99NKLN  0.01BCZT and NKLN produced by the MACSM, and for 0.95K0.5Na0.5NbO3•0.05CaTi0.9 Zr0.1O3 (0.95KNN 0.05CTZ) produced by the oxide mixing method (OMM) for comparison. The d33 value for NKLNCZT2 is approximately 1.3 and 1.6 times higher than those for 0.99NKLN  0.01BCZT [9] and NKLN [8], respectively. In addition, the MACSM allows a reduction of 50  130  C in the firing temperature and yields an increase of 74 C in Tc compared with those for 0.95KNN 0.05CTZ [20] produced by the OMM.…”

“…In 2004, Guo et al reported that (Na,K,Li)NbO3, which is produced by isovalent replacement of Li ions at the A-sites in the NKN perovskite structure, exhibited excellent piezoelectric properties and a high Tc of  450  C [7]. Moreover, Nakai et al revealed that (Na0.50K0.45Li0.05)Nb03 (NKLN) solid solutions produced by a malic acid complex solution method (MACSM) involving sintering at 950 C, which is somewhat lower than the temperature used in conventional processes, exhibited a d33 of 151 pC/N, a kp of 32%, and a Tc of 462  C [8]. Furthermore, Takada et al reported that 0.99(Na0.50K0.45Li0.05)NbO3  0.01(Ba0.85Ca0.15)(Zr0.1-Ti0.9)O3 [0.99NKLN  0.01BCZT] solid solutions produced by MACSM had excellent piezoelectric properties, with a d33 of 177 pC/N and a kp of 33%.…”

Piezoelectric Properties and Local Structure Analysis of (1-<i>x</i>)(Na_0.50K_0.45Li_0.05)NbO₃-<i>x</i>(Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃ Solid Solutions Produced by Malic Acid Complex Solution Method

“…In 2004, Guo et al reported that (Na,K,Li)NbO 3 , which is produced by isovalent replacement of Li ions at the A-sites in the NKN perovskite structure, exhibited excellent piezoelectric properties and a high T c of more than 450C [6]. Moreover, Nakai et al who were members of our research group, revealed that (Na 0.50 K 0.45 Li 0.05 )NbO 3 (NKLN) solid solutions produced by the malic acid complex solution method (MACSM) were soft materials exhibiting excellent piezoelectric properties, with a d 33 of 151 pC/N, a k p of 32% and a radial-mode mechanical quality factor Q m (p) of 87, and a high T c of 462C [7]. Meanwhile Ba(Zr 0.2 Ti 0.8 )O 3 x(Ba 0.7 Ca 0.3 )TiO 3 (BZTxBCT) solid solutions with the same crystal structure as NKLN have attracted much attention due to their good piezoelectric properties at the tricritical point of the morphotropic phase boundary (MPB) between the rhombohedral (R) and tetragonal (T) phases [8][9][10][11][12].…”