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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.


Related in: MedlinePlus

Temperature dependence of the measured electrical properties of batisite.Dielectric constant (a) and conductivity (b) are show as obtained at various frequencies (for the sake of clarity, curves are only shown for part of the investigated frequencies). The inset shows the conductivity at 1 Hz, which corresponds to the dc conductivity at T > 400 K, in an Arrhenius representation.
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f1: Temperature dependence of the measured electrical properties of batisite.Dielectric constant (a) and conductivity (b) are show as obtained at various frequencies (for the sake of clarity, curves are only shown for part of the investigated frequencies). The inset shows the conductivity at 1 Hz, which corresponds to the dc conductivity at T > 400 K, in an Arrhenius representation.

Mentions: Figure 1 shows the temperature dependence of the dielectric constant ε′ (a) and the conductivity σ′ (b) of batisite as measured for various frequencies. At high frequencies, ε′(T) exhibits moderate temperature dependence only; e.g., for 3.53 MHz it increases by about a factor of three between 62 and 666 K [Fig. 1(a)]. In contrast, at low frequencies ε′(T) rises up to about 104 at high temperatures. Such high values of the dielectric constant, sometimes termed “colossal dielectric constants”, can be caused by many different physical mechanisms8, including ferroelectric ordering. In a typical ferroelectric, when approaching the phase transition at Tc from high temperatures, ε′(T) strongly increases and starts to decrease again below Tc7. Thus, when considering the 1 Hz curve in Fig. 1(a), at first glance one may suspect a ferroelectric phase transition at a temperature beyond the investigated temperature range. However, the strong frequency dependence of ε′, observed already at very low frequencies, speaks against ferroelectric ordering of batisite.


Dielectric characterization of a nonlinear optical material.

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

Temperature dependence of the measured electrical properties of batisite.Dielectric constant (a) and conductivity (b) are show as obtained at various frequencies (for the sake of clarity, curves are only shown for part of the investigated frequencies). The inset shows the conductivity at 1 Hz, which corresponds to the dc conductivity at T > 400 K, in an Arrhenius representation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Temperature dependence of the measured electrical properties of batisite.Dielectric constant (a) and conductivity (b) are show as obtained at various frequencies (for the sake of clarity, curves are only shown for part of the investigated frequencies). The inset shows the conductivity at 1 Hz, which corresponds to the dc conductivity at T > 400 K, in an Arrhenius representation.
Mentions: Figure 1 shows the temperature dependence of the dielectric constant ε′ (a) and the conductivity σ′ (b) of batisite as measured for various frequencies. At high frequencies, ε′(T) exhibits moderate temperature dependence only; e.g., for 3.53 MHz it increases by about a factor of three between 62 and 666 K [Fig. 1(a)]. In contrast, at low frequencies ε′(T) rises up to about 104 at high temperatures. Such high values of the dielectric constant, sometimes termed “colossal dielectric constants”, can be caused by many different physical mechanisms8, including ferroelectric ordering. In a typical ferroelectric, when approaching the phase transition at Tc from high temperatures, ε′(T) strongly increases and starts to decrease again below Tc7. Thus, when considering the 1 Hz curve in Fig. 1(a), at first glance one may suspect a ferroelectric phase transition at a temperature beyond the investigated temperature range. However, the strong frequency dependence of ε′, observed already at very low frequencies, speaks against ferroelectric ordering of 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.


Related in: MedlinePlus