Dielectric properties of the bulk and interfacial layers in ferroelectric BaZr0.2Ti0.8O3 thin films

• Published in: Ceramics international Vol. 45; no. 8; pp. 10917 - 10923
• Main Authors: Wu, Muying, Li, Xiaopeng, Yu, Shihui, Sun, Yongtao, Dong, Helei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2019
• Subjects: BaZr0.2Ti0.8O3 (BZT) thin films; Bulk and interfacial layers; Dielectric properties; Bulk and interfacial layers; Dielectric properties; BaZr0.2Ti0.8O3 (BZT) thin films
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2019.02.171

The BaZr0.2Ti0.8O3 (BZT) thin films with various thicknesses are prepared to investigate the dielectric properties of their bulk and interfacial layers. The dielectric constant of 891 and loss tangent of 0.0112 for the bulk layers are obtained according to a series capacitance model. The thickness (10.3 nm) of the interfacial layers is gotten via measurement and calculation of optical refractive characteristics of the BZT thin films. Combining the above data, the dielectric constant and loss tangent of the interfacial layers are calculated to be 46.7 and 0.0413, respectively. This study shows that dielectric constant of the interfacial layer is independent of the frequency and the bias field whereas that of the bulk layers has a power law dependence on frequency. Besides, the dielectric constant of the bulk layers decreases with the increase of temperature while that of the interface layers increases with the increase of temperature. The bulk layers show a large tunability of 76.2%, a low loss tangent of 0.0065 and a high figure of merit of 117.