This title appears in the Scientific Report :
2016
Please use the identifier:
http://hdl.handle.net/2128/12509 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.93.224107 in citations.
Electronic characterization of polar nanoregions in relaxor-type ferroelectric NaNbO3 films
Electronic characterization of polar nanoregions in relaxor-type ferroelectric NaNbO3 films
Strained NaNbO3 films of different thicknesses are epitaxially grown on (110) NdGaO3 substrates. A detailedanalysis of the permittivity of these films demonstrates that strain not only leads to a modification of thepermittivity and the ferroelectric transition temperature, it also results in a prono...
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Personal Name(s): | Cai, Biya |
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Schwarzkopf, J. / Hollmann, E. / Braun, D. / Schmidbauer, M. / Grellmann, Thomas / Wördenweber, R. (Corresponding author) | |
Contributing Institute: |
JARA-FIT; JARA-FIT Bioelektronik; PGI-8 |
Published in: | Physical Review B Physical review / B, 93 93 (2016 2016) 22 22, S. 224107 224107 |
Imprint: |
College Park, Md.
APS
2016
|
DOI: |
10.1103/PhysRevB.93.224107 |
Document Type: |
Journal Article |
Research Program: |
Controlling Configuration-Based Phenomena |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.93.224107 in citations.
Strained NaNbO3 films of different thicknesses are epitaxially grown on (110) NdGaO3 substrates. A detailedanalysis of the permittivity of these films demonstrates that strain not only leads to a modification of thepermittivity and the ferroelectric transition temperature, it also results in a pronounced relaxor-type behavior andallows a direct estimation of the size and mobility of the polar nanoregions (PNRs). The compressive strain reducesthe transition temperature to 125 K and enhances the corresponding permittivity up to ε ≈ 1500 for the thinnestfilm. Since the strain relaxes with increasing film thickness, both effects, reduction of phase transition temperatureand enhancement of ε, depend on the thickness of the film. The films show a characteristic frequency and electricfield dependence of ε, which is discussed in terms of the Vogel-Fulcher equation and Rayleigh law, respectively.Using the electric field dependence of the resulting freezing temperature TVF, allows a direct estimation of thevolume of the PNRs at the freezing temperature, i.e. from 70 to 270 nm3. Assuming an idealized spherical shapeof the PNRs, diameters of a few nanometers (5.2–8 nm) are determined that depend on the applied ac electricfield. The irreversible part of the polarization seems to be dominated by the presence and mobility of the PNRs. Itshows a characteristic peak at low temperature around TVF, vanishes at a temperature where the activation energyof the PRNs extrapolates to zero, and shows a frequency dispersion that is characteristic for relaxor-type behavior. |