title: Extremely high tunability and low loss in nanoscaffold ferroelectric films.
abstract: There are numerous radio frequency and microwave device applications which require materials with high electrical tunability and low dielectric loss. For phased array antenna applications there is also a need for materials which can operate above room temperature and which have a low temperature coefficient of capacitance. We have created a nanoscaffold composite ferroelectric material containing Ba(0.6)Sr(0.4)TiO(3) and Sm(2)O(3) which has a very high tunability which scales inversely with loss. This behavior is opposite to what has been demonstrated in any previous report. Furthermore, the materials operate from room temperature to above 150 °C, while maintaining high tunability and low temperature coefficient of tunability. This new paradigm in dielectric property control comes about because of a vertical strain control mechanism which leads to high tetragonality (c/a ratio of 1.0126) in the BSTO. Tunability values of 75% (200 kV/cm field) were achieved at room temperature in micrometer thick films, the value remaining to >50% at 160 °C. Low dielectric loss values of <0.01 were also achieved, significantly lower than reference pure films.
authors: Department of Materials Science, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
authors: OonJew
authors: O
authors: Lee
authors: Sophie A
authors: SA
authors: Harrington
authors: Ahmed
authors: A
authors: Kursumovic
authors: Emmanuel
authors: E
authors: Defay
authors: Haiyan
authors: H
authors: Wang
authors: Zhenxing
authors: Z
authors: Bi
authors: Chen-Fong
authors: CF
authors: Tsai
authors: Li
authors: L
authors: Yan
authors: Quanxi
authors: Q
authors: Jia
authors: Judith L
authors: JL
authors: MacManus-Driscoll