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Dielectric characterization of a nonlinear optical material.

Lunkenheimer P, Krohns S, Gemander F, Schmahl WW, Loidl A - Sci Rep (2014)

Bottom Line: No evidence for ferro- or antiferroelectric polarization is found.As the second-harmonic generation observed in batisite points to a non-centrosymmetric structure, this material is piezoelectric, but most likely not ferroelectric.In addition, we found evidence for hopping charge transport of localized charge carriers and a relaxational process at low temperatures.

View Article: PubMed Central - PubMed

Affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany.

ABSTRACT
Batisite was reported to be a nonlinear optical material showing second harmonic generation. Using dielectric spectroscopy and polarization measurements, we provide a thorough investigation of the dielectric and charge-transport properties of this material. Batisite shows the typical characteristics of a linear lossy dielectric. No evidence for ferro- or antiferroelectric polarization is found. As the second-harmonic generation observed in batisite points to a non-centrosymmetric structure, this material is piezoelectric, but most likely not ferroelectric. In addition, we found evidence for hopping charge transport of localized charge carriers and a relaxational process at low temperatures.

No MeSH data available.


Ferroelectric polarization P of batisite.P is shown as a function of external electric field E at 113 Hz and three temperatures (symbols). The coloured lines show the results corrected for loss contributions by subtracting horizontal ellipses. The grey dashed lines are linear fits demonstrating a perfectly linear behaviour of the corrected P(E) curves.
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f4: Ferroelectric polarization P of batisite.P is shown as a function of external electric field E at 113 Hz and three temperatures (symbols). The coloured lines show the results corrected for loss contributions by subtracting horizontal ellipses. The grey dashed lines are linear fits demonstrating a perfectly linear behaviour of the corrected P(E) curves.

Mentions: To further investigate the possible occurrence of ferroelectricity in batisite, Fig. 4 shows the results of electric-field dependent polarization measurements performed between 60 and 600 K. For ferroelectric materials, characteristic P(E) hysteresis curves exhibiting a saturation of P at high absolute values of the field are expected7. However, Fig. 3 reveals purely elliptical hysteresis loops without any trace of saturation effects. Such behaviour is typical for lossy capacitors and can be explained without invoking any ferroelectric ordering when considering the relation P = ε0(ε − 1)E. For any dielectric material, contributions to the dielectric loss (e.g., the dc conductivity) make ε a complex quantity. This causes a phase shift between P and E explaining the observed ellipses. Subtracting a horizontal ellipse from the measured hysteresis should correct for these loss contributions and reveal the in-phase component only. For the present results this procedure leads to the solid lines in Fig. 4. The grey dashed lines represent linear fit curves, demonstrating purely linear polarization in batisite.


Dielectric characterization of a nonlinear optical material.

Lunkenheimer P, Krohns S, Gemander F, Schmahl WW, Loidl A - Sci Rep (2014)

Ferroelectric polarization P of batisite.P is shown as a function of external electric field E at 113 Hz and three temperatures (symbols). The coloured lines show the results corrected for loss contributions by subtracting horizontal ellipses. The grey dashed lines are linear fits demonstrating a perfectly linear behaviour of the corrected P(E) curves.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4127497&req=5

f4: Ferroelectric polarization P of batisite.P is shown as a function of external electric field E at 113 Hz and three temperatures (symbols). The coloured lines show the results corrected for loss contributions by subtracting horizontal ellipses. The grey dashed lines are linear fits demonstrating a perfectly linear behaviour of the corrected P(E) curves.
Mentions: To further investigate the possible occurrence of ferroelectricity in batisite, Fig. 4 shows the results of electric-field dependent polarization measurements performed between 60 and 600 K. For ferroelectric materials, characteristic P(E) hysteresis curves exhibiting a saturation of P at high absolute values of the field are expected7. However, Fig. 3 reveals purely elliptical hysteresis loops without any trace of saturation effects. Such behaviour is typical for lossy capacitors and can be explained without invoking any ferroelectric ordering when considering the relation P = ε0(ε − 1)E. For any dielectric material, contributions to the dielectric loss (e.g., the dc conductivity) make ε a complex quantity. This causes a phase shift between P and E explaining the observed ellipses. Subtracting a horizontal ellipse from the measured hysteresis should correct for these loss contributions and reveal the in-phase component only. For the present results this procedure leads to the solid lines in Fig. 4. The grey dashed lines represent linear fit curves, demonstrating purely linear polarization in batisite.

Bottom Line: No evidence for ferro- or antiferroelectric polarization is found.As the second-harmonic generation observed in batisite points to a non-centrosymmetric structure, this material is piezoelectric, but most likely not ferroelectric.In addition, we found evidence for hopping charge transport of localized charge carriers and a relaxational process at low temperatures.

View Article: PubMed Central - PubMed

Affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany.

ABSTRACT
Batisite was reported to be a nonlinear optical material showing second harmonic generation. Using dielectric spectroscopy and polarization measurements, we provide a thorough investigation of the dielectric and charge-transport properties of this material. Batisite shows the typical characteristics of a linear lossy dielectric. No evidence for ferro- or antiferroelectric polarization is found. As the second-harmonic generation observed in batisite points to a non-centrosymmetric structure, this material is piezoelectric, but most likely not ferroelectric. In addition, we found evidence for hopping charge transport of localized charge carriers and a relaxational process at low temperatures.

No MeSH data available.