In-plane and out-of-plane ferroelectric instabilities in epitaxial SrTiO3 films.
The in-plane and out-of-plane ferroelectric instabilities in compressed (100)-epitaxial SrTiO3 films were examined by infrared reflection spectroscopy. The strongly stiffened in-plane soft mode frequency softened very slowly on cooling. On the other hand, the silent mode appeared at around 150 K, indicating an out-of-plane ferroelectric transition. This behavior points to a split of in-plane and out-of-plane ferroelectric instability temperatures due to the lowered symmetry of the SrTiO3 lattice caused by mechanical misfit strain. Infrared spectroscopy provides a possibility to detect such an effect in the strained epitaxial ferroelectric films.
Yamada
T
T
Ceramics Laboratory, Swiss Federal Institute of Technology, EPFL, CH-1015 Lausanne, Switzerland. tomoaki.yamada@epfl.ch
Petzelt
J
J
Tagantsev
A K
AK
Denisov
S
S
Noujni
D
D
Petrov
P K
PK
Mackova
A
A
Fujito
K
K
Kiguchi
T
T
Shinozaki
K
K
Mizutani
N
N
Sherman
V O
VO
Muralt
P
P
Setter
N
N