An improved Bridgman-Stockbarger crystal-growth system

Nicoarǎ, Dumitru; Nicoarǎ, Irina

doi:10.1016/0025-5416(88)90584-8

Cited by 42 publications

(24 citation statements)

References 10 publications

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“…The crystals were obtained in graphite crucible in vacuum (∼10 −1 Pa). In order to obtain the temperature distribution and optimum temperature gradient necessary for the growth process we used a shaped graphite furnace [12]. The pulling rate was 4 mm h −1 .…”

Section: Methodsmentioning

confidence: 99%

Charge compensating defects study of YbF‐doped BaF crystals using dielectric loss

Nicoarǎ

Stef

2015

Physica Status Solidi (b)

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YbF3‐doped BaF2 crystals with various concentrations of YbF3 (0.05, 0.1, 0.17, 0.2 mol%) have been grown using the conventional Bridgman method. Dielectric relaxation is used to study the charge compensating defects in BaF2 crystals with low YbF3 concentration. The optical absorption spectra reveal the existence of both Yb2+ (in UV domain) and Yb3+ (in IR domain) ions. In the investigated temperature range (150–320 K) we have observed only one type of dielectric relaxation. This relaxation with activation energy E=0.54 eV is associated with trigonal‐type (C3v) centers. The charge compensating defects are discussed while taking also into account the optical absorption spectra and the calculated number of NNN dipoles whose relaxation is observed.

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Section: Methodsmentioning

confidence: 99%

Charge compensating defects study of YbF‐doped BaF crystals using dielectric loss

Nicoarǎ

Stef

2015

Physica Status Solidi (b)

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“…Pure, YbF 3 -doped and LiF-, NaF-codoped CaF 2 crystals have been grown in our crystal research laboratory using vertical Bridgman method [10]. Suprapure grade (Merck) calcium fluoride, YbF 3 , LiF and NaF were used as the starting materials.…”

Section: Methodsmentioning

confidence: 99%

“…To prevent the evaporation of the NaF and LiF, a thin graphite lid was put on the charge in the crucible. Transparent colorless crystals of about 10 mm diameter over 6-7 m long were obtained in spectral pure graphite crucible in vacuum (≈ 10 −1 Pa) using a shaped graphite furnace [10]. The crystals have been cooled to room temperature using an established procedure.…”

Section: Methodsmentioning

confidence: 99%

Influence of Various Impurities on the Optical Properties of YbF₃-Doped CaF₂Crystals

et al. 2007

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Calcium fluoride crystals doped with YbF3 and co-doped with LiF and NaF were grown using the vertical Bridgman method. Several of rare-earth ions (such as Eu, Sm, Ho, Tm, and Yb) can be stabilized in the divalent state in the CaF2. The change of valence was attained by various methods. The optical absorption spectra reveal the characteristic absorption bands of the Yb 3+ and Yb 2+ ions. This means that the developed crystal growth process achieves a good Yb 3+ to Yb 2+ conversion in the as-grown crystals. The influence of other impurities, such as Na + or Li + , on the absorption and emission spectrum of YbF 3 -doped CaF 2 was studied. The Li + and Na + ions drastically decrease the absorption coefficient of the Yb 2+ ions in the UV band and the emission intensity by excitation in 230 nm.

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“…BaF 2 crystal doped with 0.17 mol% YbF 3 was grown in our crystal research laboratory using vertical Bridgman method [4] in graphite crucible, in vacuum (~10 -3 torr). Supra-pure grade (Merck) BaF 2 and YbF 3 were used as the starting materials.…”

Section: Methodsmentioning

confidence: 99%

Segregation coefficient of Yb3+ and Yb2+ ions in YbF3 doped BaF2 crystals

Nicoarǎ¹,

Buşe²,

Bunoiu³

2014

AIP Conference Proceedings

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Abstract. BaF 2 :0.17 mol%YbF 3 crystal was grown using the conventional Bridgman technique. The optical absorption spectra reveal the existence of both Yb 2+ and Yb 3+ ions with the characteristic bands of the trivalent ions in the near-IR region and of the divalent ions in the UV spectral domain. The concentration distribution of the Yb 2+ and Yb 3+ ions among the sample was investigated using the optical absorption method. The segregation coefficient of the two types of Yb ions has been determined. From our calculations the segregation coefficient of the Yb 3+ ions in BaF 2 host is ≈ 0.7, and of the Yb 2+ ions is ≈ 0.6.

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An improved Bridgman-Stockbarger crystal-growth system

Cited by 42 publications

References 10 publications

Charge compensating defects study of YbF‐doped BaF crystals using dielectric loss

Charge compensating defects study of YbF‐doped BaF crystals using dielectric loss

Influence of Various Impurities on the Optical Properties of YbF₃-Doped CaF₂Crystals

Segregation coefficient of Yb3+ and Yb2+ ions in YbF3 doped BaF2 crystals

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An improved Bridgman-Stockbarger crystal-growth system

Cited by 42 publications

References 10 publications

Charge compensating defects study of YbF‐doped BaF crystals using dielectric loss

Charge compensating defects study of YbF‐doped BaF crystals using dielectric loss

Influence of Various Impurities on the Optical Properties of YbF3-Doped CaF2Crystals

Segregation coefficient of Yb3+ and Yb2+ ions in YbF3 doped BaF2 crystals

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Influence of Various Impurities on the Optical Properties of YbF₃-Doped CaF₂Crystals