Ferroelectric domain wall relaxation in Ba{sub 0.25}Sr{sub 0.75}TiO{sub 3} films displaying Curie-Weiss behavior

Journal Article · Fri Oct 15 00:00:00 EDT 2004 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1787587· OSTI ID:20662112

Boikov, Yu A; Khamchane, K; Claeson, T ^[1]

---

1. Microtechnology and Nanoscience, Quantum Device Physics Laboratory, Chalmers University of Technology, SE-412 96 Goeteborg, Sweden and Ioffe Physico-Technical Institute Russian Academy of Science, 194 021 St. Petersburg (Russian Federation)

Ferroelectric films may be used in integrated circuits for high frequency and memory applications. Losses and interfaces between films and electrodes are problematic. This work concerns the temperature and electric field response of the complex dielectric permittivity and the relaxation of domain walls in a ferroelectric layer that is of sufficient quality to show a Curie-Weiss behavior. Laser ablation was used to deposit 1200 nm thick Ba{sub 0.25}Sr{sub 0.75}TiO{sub 3} layers between metallic oxide (100 nm) SrRuO{sub 3} and (120 nm) La{sub 0.67}Ca{sub 0.33}MnO{sub 3}, films in epitaxial heterostructures. The electric field response (E{<=}80 kV/cm) of the real {epsilon}{sup '} and imaginary {epsilon}{sup ''} parts of the complex permittivity of the intermediate Ba{sub 0.25}Sr{sub 0.75}TiO{sub 3} layer in these parallel plane film capacitors was studied at temperatures above and below the phase transition point T{sub Curie}. The latter was determined from the temperature dependence of the inverse dielectric permittivity and its value, T{sub Curie}=145 K, agrees well with that of bulk single crystal. {epsilon}{sup '} of the Ba{sub 0.25}Sr{sub 0.75}TiO{sub 3} layer could be suppressed about 80% by a field E=80 kV/cm at temperatures close to T{sub Curie}{epsilon}{sup '}(T,E) and {epsilon}{sup ''}(T,E) curves were used to gain insight into the relaxation dynamics of ferroelectric domain walls (DW) in the Ba{sub 0.25}Sr{sub 0.75}TiO{sub 3} layer. Their influence on {epsilon}{sup '} was noticed up to T=230 K, well above T{sub Curie}. The most probable relaxation time {tau} of the DW in Ba{sub 0.25}Sr{sub 0.75}TiO{sub 3} follows a relation {tau}={tau}{sub 0} exp[({phi}-{beta}{radical}(E))/kT], where {tau}{sub 0}=1.2x10{sup -10} s {phi}=75-105 meV, and {beta}=4.7x10{sup -24} J m{sup 1/2} V{sup -1/2}.

• OSTI ID: 20662112
• Journal Information: Journal of Applied Physics, Vol. 96, Issue 8; Other Information: DOI: 10.1063/1.1787587; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABLATION
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CAPACITORS
CURIE POINT
CURIE-WEISS LAW
EPITAXY
FERROELECTRIC MATERIALS
GRAIN BOUNDARIES
LANTHANUM COMPOUNDS
MANGANESE OXIDES
MEV RANGE 10-100
MONOCRYSTALS
PERMITTIVITY
PHASE TRANSFORMATIONS
RELAXATION
RELAXATION TIME
STRONTIUM TITANATES
TEMPERATURE DEPENDENCE
THIN FILMS