Effect of La and Mn on the properties of alkaline niobate-based piezoelectric ceramics

Peer review under responsibility of The Ceramic Society of Japan and the Korean Ceramic Society.

Figures & data

Table 1 Data showing the density, dielectric and piezoelectric properties of (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ ceramics co-doped with different amounts of La and Mn at room temperature.

Doping amount (mol%)	ɛr @ 1 kHz	tan δ (1 kHz)	d33 (pC/N)	Normalised strain, $d_{33}^{*}$ (pm/V)	Theoretical density (g/cm^3)	Relative density (%)	Remnant polarisation, Pr (μC/cm^2)	Coercive field, Ec (kV/cm)
0	∼1146	0.1515	220	400 ± 10	4.79	94.25 ± 2.3	∼18.9	8.55
0.25	∼1397	0.0812	196	259 ± 5	4.81	93.87 ± 0.6	∼10.0	6.57
0.5	∼1311	0.0283	167	283 ± 5	4.82	94.87 ± 0.9	∼10.0	6.57
1.0	∼1357	0.0293	159	157 ± 4	4.84	90.96 ± 0.5	∼7.5	6.57

Fig. 1 Scanning electron microscope images of the thermally etched surfaces of (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ ceramics sintered at 1075 °C for 1 h in air atmosphere showing (a) the undoped ceramic, (b) ceramic with 0.25 mol% of La, Mn and (c) with 0.5 mol% of La, Mn.

Fig. 2 X-ray diffraction patterns of (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ ceramics doped with different amounts of dopants. Traces of an extra phase can be observed on the pattern containing 1 mol% of La and Mn.

Fig. 3 Temperature dependence of (a) the dielectric constant values for (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ ceramics measured at 1 kHz and (b) the dielectric loss (tan δ) values for (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ ceramics measured at 1 kHz. The inset in the graph magnifies the region of the graph from 20 °C to 250 °C and from 20 °C to 300 °C for (a) and (b), respectively.

Fig. 4 A plot of the polarisation–electric field hysteresis curves for (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ ceramics co-doped with different amounts of La and Mn.

Fig. 5 A plot of the strain–electric field hysteresis curves for (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ ceramics co-doped with different amounts of La and Mn.