title: Structures, Phase Transformations, and Dielectric Properties of BiTaO4Ceramics.
abstract: Low (α)- and high-temperature (β) forms of BiTaO4have attracted much attention due to their dielectric and photocatalytic properties. In the present work, a third form, the so-called HP-BiTaO4, was synthesized at high temperature and pressure. The phase evolution, phase transformations, and dielectric properties of α- and β-BiTaO4and HP-BiTaO4ceramics are studied in detail. β-BiTaO4ceramics densified at 1300 °C with the microwave permittivity εr≈ 53, the microwave quality factor Qf≈ 12070 GHz, and the temperature coefficient of resonant frequency τf≈ -200 ppm/°C. HP-BiTaO4ceramics were synthesized at 5 GPa and 1300 °C followed by annealing at 600 °C. In contrast with the α phase, HP-BiTaO4exhibited εr≈ 195 at 1 kHz to 10 MHz, accompanied by a low dielectric loss of ∼0.004. The relation between structure and dielectric properties is discussed in the context of Shannon's additive rule and bond theory.
authors.affiliation: Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, Shaanxi, People's Republic of China.|Department of Materials Science and Engineering, University of Sheffield , Sheffield S1 3JD, U.K.
authors.forename: Di
authors.initials: D
authors.lastname: Zhou
authors.affiliation: Institute of Atomic and Molecular Physics, Sichuan University , Chengdu 610065, People's Republic of China.
authors.forename: Xiao-Qin
authors.initials: XQ
authors.lastname: Fan
authors.affiliation: Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, Shaanxi, People's Republic of China.
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Jin
authors.affiliation: Institute of Atomic and Molecular Physics, Sichuan University , Chengdu 610065, People's Republic of China.
authors.forename: Duan-Wei
authors.initials: DW
authors.lastname: He
authors.affiliation: Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology , Guilin 541004, People's Republic of China.
authors.forename: Guo-Hua
authors.initials: GH
authors.lastname: Chen