کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1474707 | 991096 | 2014 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Evolution of structure and electrical properties with lanthanum content in [(Bi1/2Na1/2)0.95Ba0.05]1−xLaxTiO3 ceramics Evolution of structure and electrical properties with lanthanum content in [(Bi1/2Na1/2)0.95Ba0.05]1−xLaxTiO3 ceramics](/preview/png/1474707.png)
Lead-free perovskite [(Bi1/2Na1/2)0.95Ba0.05]1−xLaxTiO3 (x = 0.00–0.10) ceramics were fabricated via the solid state reaction method and their crystal structures and electrical properties were systematically studied. Transmission electron microscopy examination reveals a transition from a rhombohedral R3c phase with micron-sized complex domains to a mixture of rhombohedral R3c and tetragonal P4bm phases with nanodomains as La content was increased. X-ray diffraction analysis on bulk samples, however, indicates a pseudocubic structure in La-doped compositions. Electrical poling seems to transform the pseudocubic structure to a rhombohedral phase in compositions with 0.00 < x < 0.03. With La addition, the depolarization temperature (Td) is observed to decrease and the dielectric constant (ɛr) within 100–350 °C becomes more temperature independent, promising for applications in high-temperature capacitors. Electric field-induced polarizations and strains display complex changes with respect to La concentration, with the highest strain of 0.35% achieved in the composition x = 0.04 under 70 kV/cm at room temperature. The piezoelectric coefficient d33 initially increases with La content, reaching a maximum value of 151 pC/N in the composition x = 0.02, and then diminishes.
Journal: Journal of the European Ceramic Society - Volume 34, Issue 12, October 2014, Pages 2997–3006