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Polarization switching and relaxation dynamics of bismuth layered ferroelectric thin films: Role of oxygen defect sites and crystallinity

Title
Polarization switching and relaxation dynamics of bismuth layered ferroelectric thin films: Role of oxygen defect sites and crystallinity
Authors
Lee J.H.Shin R.H.Jo W.
Ewha Authors
조윌렴
SCOPUS Author ID
조윌렴scopus
Issue Date
2011
Journal Title
Physical Review B - Condensed Matter and Materials Physics
ISSN
1098-0121JCR Link
Citation
vol. 84, no. 9
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Influence of oxygen vacancies and crystallinity on polarization switching and relaxation dynamics of Bi3.15Nd0.85Ti 3O12 (BNT) thin films on Pt electrodes have been studied by piezoresponse force microscopy (PFM). Heat treatment of the study induced oxygen vacancies in Bi2O2 +2 layers not in TiO6 -8 octahedra and changes in crystallinity of the films. Oxygen atoms have two different locations unique in the bismuth layered ferroelectrics and, in particular, the oxygen vacancies at the Bi 2O2 +2 layers turned out to be critical for retention of polarization states. Perfect crystallinity in the arrangement of atoms through c-axis is surprisingly found to sustain polarization switching. Electrodynamics of the bound charges in the films with oxygen deficiency and imperfectness of crystallinity are presented in a dynamic model with random-walk motion of point defects and a diffusive migration of mobile and bound charges and their clusters. For the stretched exponential decay of the bound charges in the films, the scaling exponents are 0.086 and 0.289 for well crystalline-thin films. © 2011 American Physical Society.
DOI
10.1103/PhysRevB.84.094112
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자연과학대학 > 물리학전공 > Journal papers
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