Effect of Anneal Conditions on Electrical Properties of Mn-Doped (Na0.85K0.15)0.5Bi0.5TiO3 Thin Films Prepared by Sol–Gel Method
Authors: Wu, Yunyi; Wang, Xiaohui; Zhong, Caifu; Li, Longtu
Source: Journal of the American Ceramic Society, Volume 94, Number 6, June 2011 , pp. 1843-1849(7)
Abstract:Mn-doped (Na0.85K0.15)0.5Bi0.5TiO3 (NKBT-Mn) thin films were fabricated on Pt(111)/Ti/SiO2/Si substrates via an aqueous sol–gel method and annealed at different temperatures from 550° to 800°C. Two different crystallization processes, i.e., single crystallization and multiple crystallizations, were used. The structures of the films were analyzed using X-ray diffraction, which shows that the NKBT-Mn thin film prepared by multiple crystallizations crystallize into the pure perovskite phase, while pyrochlore phase formed in the film prepared by the single crystallization. Ferroelectric and dielectric properties of NKBT-Mn thin films are quite dependent on the anneal temperature. The P r value was a maximum for the 700oC-annealed thin film and decreased with both decreasing and increasing anneal temperature. The NKBT-Mn thin film annealed at 700°C had the largest ɛr of 426 and the lowest tan δ of 0.061. At the same time, the temperature-dependent ferroelectric property was also investigated from room temperature to −150°C. It is found that P r of the film sample increases as temperature decreases, which can be well explained by a temperature-dependent charged carriers–domain wall interaction. Current density measurement indicates that the change in morphology with increasing anneal temperature and the volatility of Bi and Na/K at high temperature may responsible for the change in leakage current density and the NKBT-Mn thin film annealed at 700°C has the lowest leakage current of 7.6 × 10−5 A/cm2.
Document Type: Research Article
Affiliations: State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
Publication date: June 1, 2011