Dielectric spectrum of rare-earth-doped calcium fluoride crystals

Nicoarǎ, Irina; Munteanu, Mihai; Pecingina-Girjioaba, N.; Stef, Marius; Lighezan, Liliana

doi:10.1016/j.jcrysgro.2005.11.018

Cited by 10 publications

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“…This is investigated here in calcium fluoride crystals by considering the most recent experimental and theoretical work. In particular, concerning the experimental work, the dependence on the temperature of ε′ and ε ″ at various frequencies (1-100 kHz) for ErF 3 and YbF 3 -doped CaF 2 has been recently studied by Nicoara et al [5].…”

Section: ( )mentioning

confidence: 99%

“…Despite of the scatter, we may say that the tendency of the data seems to be consistent with model, if one recalls that the extraction of the m s -from the 0 τ -value, suffers from an arbitrary selection of the quantity , λν as explained in the previous section. [5]. The same procedure is repeated for the two relaxation peaks probably associated with tetravalent uranium ion in the system CaF 2 : U (0.1%), Na (0.1%) measured by Montgomery et al [12].…”

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confidence: 99%

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Interconnection of the parameters obtained from the dielectric spectrum of CaF₂ doped with ErF₃ and YbF₃

Vassilikou‐Dova

Katsika-Tsigourakou

2008

Physica Status Solidi (b)

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A model has been suggested long ago that interconnects point defect parameters with bulk properties. On this basis, the ra‐tio of the migration entropy sm and the migration enthalpy hm should be equal to a bulk quantity. The validity of this prediction is studied here for the migration sm deduced from the pre‐exponential factor τ0 over the activation energy E involved in the Arrhenius relation τ = τ0 exp (E /kT) for the relaxation time τ. The study is focused on the so called RI‐relaxation in CaF2 doped with ErF3 and YbF3. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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confidence: 99%

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confidence: 99%

Interconnection of the parameters obtained from the dielectric spectrum of CaF₂ doped with ErF₃ and YbF₃

Vassilikou‐Dova

Katsika-Tsigourakou

2008

Physica Status Solidi (b)

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“…The maxima of ε 2 at T max for doped CaF 2 sample are higher values than for pure sample, probable due to the more dipole type defects which are created in the doped samples. The activation parameters of the relaxation process are determined using the method described in [2,3,10] and are given in Table I. The relevant ionic radii of the cations are 1.26Å (Ca 2+ ) and 1.33Å (Pb 2+ ) shows that incorporated lead ions do not produce significant lattice distortions.…”

Section: Optical Propertiesmentioning

confidence: 99%

Dielectric Relaxation in PbF2 - Doped and X-ray Irradiated CaF2 Crystals

Nicoarǎ¹,

Munteanu²,

Pecingina-Garjoaba³

et al. 2006

ECS Trans.

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Temperature and frequency dependence of the complex dielectric constant give information about the relaxation processes and permits the determination of the activation energy and the reciprocal frequency factor of the relaxation time. Pure and various concentration PbF 2 -doped CaF 2 crystals have been grown using the vertical Bridgman method. The thin disks cut from the crystals have been X-ray irradiated. Room temperature optical absorption spectra were recorded for pure, doped and x-ray irradiated samples. Capacitance and dielectric loss measurements were performed on the samples over the temperature range 150-300 K at 1-100 kHz, and then the imaginary part of the dielectric constant has been calculated. The dielectric properties have been measured before and after X-ray irradiation, the activation energy and the reciprocal frequency factor have been calculated in order to characterize the observed relaxations.

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“…The alkaline-earth fluorides crystallize in the cubic structure and constitute an important class of relatively simple ionic crystals whose optical and lattice-dynamical properties have theoretical and experimental interest [1][2][3][4][5]. The alkaline-earth fluorides (MF 2 , M=Ca, Ba, Sr) crystals doped with rareearth (RE=La, Er, Yb, etc.)…”

Section: Introductionmentioning

confidence: 99%

Influence of some impurities on the emission properties of CaF2:YbF3 crystals

Stef

Nicoarǎ

Cirlan

et al. 2015

AIP Conference Proceedings

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Abstract. Various concentrations of YbF3 -doped and NaF or PbF2 co-doped CaF2 crystals were grown using the conventional Bridgman method. Transparent colorless crystals were obtained in graphite crucible in vacuum using a shaped graphite furnace. The crystals have been cooled to room temperature using an established procedure. Room temperature absorption spectra have been obtained using a Shimadzu 1650PC spectrophotometer. Photoluminescent properties in IR spectral range were analyzed using a spectrofluorimeter Horiba Fluorolog 3. An IR laser diode at 932 nm was also used an directly injected in the equipment. The emission spectra are influenced by the concentration of co-dopant added to the melt, and the excitation wavelength. The high emission peak at 979 nm overlaps with the absorption peak. The highest intensity in the IR emission (around 1029 nm) is obtained for CaF2:0.72 mol% YbF3 crystal by excitation at 932 nm (diode lamp).

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Dielectric spectrum of rare-earth-doped calcium fluoride crystals

Cited by 10 publications

References 14 publications

Interconnection of the parameters obtained from the dielectric spectrum of CaF₂ doped with ErF₃ and YbF₃

Interconnection of the parameters obtained from the dielectric spectrum of CaF₂ doped with ErF₃ and YbF₃

Dielectric Relaxation in PbF2 - Doped and X-ray Irradiated CaF2 Crystals

Influence of some impurities on the emission properties of CaF2:YbF3 crystals

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Dielectric spectrum of rare-earth-doped calcium fluoride crystals

Cited by 10 publications

References 14 publications

Interconnection of the parameters obtained from the dielectric spectrum of CaF2 doped with ErF3 and YbF3

Interconnection of the parameters obtained from the dielectric spectrum of CaF2 doped with ErF3 and YbF3

Dielectric Relaxation in PbF2 - Doped and X-ray Irradiated CaF2 Crystals

Influence of some impurities on the emission properties of CaF2:YbF3 crystals

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Interconnection of the parameters obtained from the dielectric spectrum of CaF₂ doped with ErF₃ and YbF₃

Interconnection of the parameters obtained from the dielectric spectrum of CaF₂ doped with ErF₃ and YbF₃