Ferroelectricity in ultrathin BaTiO3 films: probing the size effect by ultraviolet Raman spectroscopy.
We demonstrate the dramatic effect of film thickness on the ferroelectric phase transition temperature Tc in strained BaTiO3 films grown on SrTiO3 substrates. Using variable-temperature ultraviolet Raman spectroscopy enables measuring Tc in films as thin as 1.6 nm, and a film thickness variation from 1.6 to 10 nm leads to Tc tuning from 70 to about 925 K. Raman data are consistent with synchrotron x-ray scattering results, which indicate the presence of 180 degrees domains below Tc, and thermodynamic phase-field model calculations of Tc as a function of thickness.
Tenne
D A
DA
Department of Physics, Boise State University, 1910 University Drive, Boise, Idaho 83725-1570, USA. dmitritenne@boisestate.edu
Turner
P
P
Schmidt
J D
JD
Biegalski
M
M
Li
Y L
YL
Chen
L Q
LQ
Soukiassian
A
A
Trolier-McKinstry
S
S
Schlom
D G
DG
Xi
X X
XX
Fong
D D
DD
Fuoss
P H
PH
Eastman
J A
JA
Stephenson
G B
GB
Thompson
C
C
Streiffer
S K
SK