TY  - JOUR
AU  - Liang, Sijia
AU  - Pfützenreuter, D.
AU  - Finck, Dennis
AU  - von Helden, L.
AU  - Schwarzkopf, J.
AU  - Wördenweber, R.
TI  - Tunable surface acoustic waves on strain-engineered relaxor K 0.7 Na 0.3 NbO 3 thin films
JO  - Applied physics letters
VL  - 116
IS  - 5
SN  - 1077-3118
CY  - Melville, NY
PB  - American Inst. of Physics
M1  - FZJ-2020-02145
SP  - 052902 -
PY  - 2020
AB  - In this work we demonstrate the electronic tunability of surface acoustic waves (SAWs) in epitaxially strained relaxor-type ferroelectric thin films. Epitaxial K0.7Na0.3NbO3 thin films of typically 30 nm in thickness are grown via pulsed laser deposition on (110)-oriented TbScO3. A partial plastic lattice relaxation of the epitaxial strain in these samples leads to a relaxor-type ferroelectricity of these films, which strongly affects the SAW properties. Without electronic bias only tiny SAW signals of ~0.2 dB can be detected at room temperature, which can be boosted up to 4 dB by a static voltage (DC) bias added to the high frequency (HF) driving current of the SAW transducers. Upon field cooling below the freezing temperature of polar nano regions (PNRs), this strong SAW signal can be preserved and is even enhanced due to a release of the electronically fixed PNRs if the bias is removed. In contrast, at elevated temperatures, a reversible switching of the SAW signal is possible. The switching shows relaxation dynamics that are typical for relaxor ferroelectrics. The relaxation time  decreases exponentially from several hours at freezing temperature to a few seconds (<5 s) at room temperature.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000513133500013
DO  - DOI:10.1063/1.5140259
UR  - https://juser.fz-juelich.de/record/877329
ER  -