Folded acoustic phonons and soft mode dynamics in BaTiO3/SrTiO3 superlattices -: art. no. 132302

被引:44
作者
Das, RR [1 ]
Yuzyuk, YI [1 ]
Bhattacharya, P [1 ]
Gupta, V [1 ]
Katiyar, RS [1 ]
机构
[1] Univ Puerto Rico, Dept Phys, San Juan, PR 00931 USA
来源
PHYSICAL REVIEW B | 2004年 / 69卷 / 13期
关键词
D O I
10.1103/PhysRevB.69.132302
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
A series of BaTiO3/SrTiO3 superlattices with stacking periodicity of 6-10 unit cells were fabricated on (001)MgO substrates using pulsed-laser-deposition technique. Polarized Raman spectra revealed BaTiO3-like optical vibrations and confirmed tetragonal symmetry of the superlattices with the c axis being normal to the layers. Due to in-plane compressive stresses generated by the lattice mismatch of the constituting layers, the E(1TO) soft mode was underdamped and markedly shifted to higher frequencies with respect to its analogs in the bulk. The existence of perfect superlattice structure was evident from the observation of the folded acoustic phonons in Raman spectra. The frequencies of the folded phonons matched well with the calculated transverse-acoustic branches of the constituent materials. No phase transitions were revealed in the superlattices below room temperature, while phase transition to the paraelectric state is shifted up to 650-700 K and it is diffused.
引用
收藏
页码:132302 / 1
页数:4
相关论文
共 28 条
[1]   OBSERVATION OF FOLDED ACOUSTIC PHONONS IN A SEMICONDUCTOR SUPER-LATTICE [J].
COLVARD, C ;
MERLIN, R ;
KLEIN, MV ;
GOSSARD, AC .
PHYSICAL REVIEW LETTERS, 1980, 45 (04) :298-301
[2]   CHAIN STRUCTURE OF BATIO3 AND KNBO3 [J].
COMES, R ;
LAMBERT, M ;
GUINIER, A .
SOLID STATE COMMUNICATIONS, 1968, 6 (10) :715-&
[3]   Ferroelectric transition in an epitaxial barium titanate thin film: Raman spectroscopy and x-ray diffraction study [J].
El Marssi, M ;
Le Marrec, F ;
Lukyanchuk, IA ;
Karkut, MG .
JOURNAL OF APPLIED PHYSICS, 2003, 94 (05) :3307-3312
[4]   LATTICE-DYNAMICS OF CRYSTALS WITH TETRAGONAL BATIO3 STRUCTURE [J].
FREIRE, JD ;
KATIYAR, RS .
PHYSICAL REVIEW B, 1988, 37 (04) :2074-2085
[5]   NEUTRON-SCATTERING STUDYOF SOFT MODES IN CUBIC BATIO3 [J].
HARADA, J ;
AXE, JD ;
SHIRANE, G .
PHYSICAL REVIEW B-SOLID STATE, 1971, 4 (01) :155-+
[6]   COUPLED ACOUSTIC MODES IN TETRAGONAL BATIO3 [J].
ISHIDATE, T ;
SASAKI, S .
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 1987, 56 (12) :4214-4217
[7]   Phase transitions and polarizations in epitaxial BaTiO3/SrTiO3 superlattices studied by second-harmonic generation [J].
Jiang, AQ ;
Scott, JF ;
Lu, HB ;
Chen, ZH .
JOURNAL OF APPLIED PHYSICS, 2003, 93 (02) :1180-1185
[8]   Large nonlinear dielectric properties of artificial BaTiO3/SrTiO3 superlattices [J].
Kim, J ;
Kim, Y ;
Kim, YS ;
Lee, J ;
Kim, L ;
Jung, D .
APPLIED PHYSICS LETTERS, 2002, 80 (19) :3581-3583
[9]   Strain manipulation in BaTiO3/SrTiO3 artificial lattice toward high dielectric constant and its nonlinearity [J].
Kim, L ;
Jung, DG ;
Kim, J ;
Kim, YS ;
Lee, J .
APPLIED PHYSICS LETTERS, 2003, 82 (13) :2118-2120
[10]   Raman scattering study of La0.7Sr0.3MnO3/SrTiO3 multilayers [J].
Kreisel, J ;
Lucazeau, G ;
Dubourdieu, C ;
Rosina, M ;
Weiss, F .
JOURNAL OF PHYSICS-CONDENSED MATTER, 2002, 14 (20) :5201-5210