Ultralow dielectric loss in Tb plus Ta-modified TiO2 giant dielectric ceramics via designing defect chemistry

The environment-friendly materials exhibiting colossal permittivity play an increasingly important role in the electronics industry. In this work, (Tb0.5Ta0.5)(x )Ti1-xO2 (x = 0, 0.005, 0.01, 0.02, and 0.04) ceramics with new defect clusters were fabricated to enhance the dielectric response. Significantly, all ceramic samples exhibit large dielectric constants (epsilon(r) > 10(4)), whereas the ceramic with x = 0.005 exhibits an ultralow loss (tan delta) of about 0.008 at room temperature and 1 kHz. The origins of its excellent dielectric properties were revealed by XRD, X-ray photoelectron spectroscopy, and dielectric response analysis, which were mainly caused by defective dipoles associated with oxygen vacancies ((V) over dot(O)). These defective dipoles limiting the long-range hopping of electrons lead to the electron pinning effect. Additionally, the frequency spectrum under DC bias and conductivity behavior suggests that grain boundary and electrode effects also contribute to the dielectric constant. This study not only explores the dielectric response properties of a new giant dielectric (Tb0.5Ta0.5)(x)Ti1-xO2 ceramics but also offers a candidate material suitable for ceramics capacitors.

Automated summary

In this study, ceramics of (Tb0.5Ta0.5)(x)Ti1-xO2 with new defect clusters were fabricated, showing large dielectric constants, and one of the samples exhibited ultralow loss at room temperature and 1 kHz. The excellent dielectric properties were attributed to defective dipoles associated with oxygen vacancies, which limited the long-range hopping of electrons and caused the electron pinning effect. Grain boundary and electrode effects also contributed to the dielectric constant.