High dielectric tunability of middle entropy Pb(Sc0.25In0.25Nb0.25Ta0.25)O3 thin films with (111)-preferred orientation

Abstract

High-performance dielectric tunable materials are expected in modern tunable devices, such as phase shifters, tunable resonator, filters, and antennas, etc. In this work, two strategies were used to improve the performance of dielectric tunability of perovskite oxide thin films: (ⅰ) a middle entropy perovskite oxide Pb(Sc0.25In0.25Nb0.25Ta0.25)O3 (PSINT) was designed to enhance displacement polarization; (ⅱ) preferred orientation of the PSINT thin films derived by sol-gel method was modified by substrates. A high dielectric tunability (η ~ 50 %) with a high dielectric tunability strength (η/E ~ 0.12 % cm/kV) was achieved at a low electric field of ~ 407 kV/cm in the highly (111)-oriented PSINT thin film. Increase the applied electric field, a higher dielectric tunability (ηmax ~ 65 %) was achieved at ~ 679 kV/cm. Moreover, an excellent thermal stability with a broad working temperature from 223 K to 423 K was obtained, which could be credited to a large relaxor strength of the thin film. The results indicate that the middle entropy PSINT thin film with (111)-orientation has a potential application in modern tunable devices.