The effect of growth atmosphere and Ir contamination on electric properties of La3Ta0.5Ga5.5O14 single crystal grown by the floating zone and Czochralski method

Kimura, Hiromitsu; Uda, Satoshi; Бузанов, О. А.; Huang, Xinming; Koh, Shinji

doi:10.1007/s10832-007-9349-2

Cited by 32 publications

(22 citation statements)

References 12 publications

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“…LGT crystals are commonly grown by Czochralski method using an Iridium crucible [5] [6] [10] [15]. Kimura et al [15] reported that LGT crystals contain iridium ions, which are responsible to the crystal color.…”

Section: Metal Ions Impuritiesmentioning

confidence: 99%

“…Kimura et al [15] reported that LGT crystals contain iridium ions, which are responsible to the crystal color. However, Fs LA-ICP-MS chemical analyses [3] show that iridium concentration in LGT crystals is below 1 ppm.…”

Section: Metal Ions Impuritiesmentioning

confidence: 99%

“…LGT crystal color depends on the growth atmosphere and the post growth treatment, and it is H. Kimura et al [15] and O.A Busanov et al [16] observed that the color of LGS and LGT crystals depends on the oxygen partial pressure in growth atmosphere. The color of LGT crystals decreases progressively in intensity when the Oxygen concentration in an Argon-Oxygen growth atmosphere is reduced [16].…”

Section: Electron Color Centersmentioning

confidence: 99%

“…According to Buzanov et al [6], LGT crystals color depends not only on oxygen vacancies but also on cation vacancies and charge exchange in cations. In the opinion of the authors [15], LGT crystals contain iridium ions, which induce its color on the basis that LGT crystals grown from a Pt crucible in air were colorless [6]. However, Taishi et al [14] obtained orange crystals by Bridgman growth in Pt crucible.…”

Section: Introductionmentioning

confidence: 99%

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Color Origins in Langatate Crystals

Allani¹,

Batis²,

Nehari³

et al. 2017

Int. Ann. Sci.

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A B S T R A C TLangatate La3Ga5.5Ta0.5O14 is piezoelectric crystal from langasite family, commonly grown by Czochralski method from Ir crucible. Langatate crystals of different colors (colorless, orange, green) have been studied by optical spectroscopy in UV-Visible (200 -800 nm) and IR (7000 -1000 cm -1 ) ranges. Furthermore, the effects of irradiation by ultraviolet laser source (λ=266 nm) and post-growth annealing in N2+O2 atmosphere have been investigated. The yellow-orange is mainly due to an absorption centered in the ultraviolet that extends into the blue of the visible spectrum (250-500 nm). The IR optical absorption spectra of Langatate crystals exhibit an absorption band at 5370 cm -1 . It seems linked to a point defect responsible for color. The intensity of the absorption band at 3430 cm -1 increases after annealing in oxygen containing atmosphere. We have discussed phenomenon that can occur simultaneously in langatate crystals and produce very similar colors which are related to structural defects. First, metal ions impurities (as Iron, Titanium…), whose presence is previously confirmed by femtosecond laser ablation coupled with ICP-MS spectroscopy, can contribute to langatate color. Second, ultraviolet absorption leads us to think about charge transfer phenomenon such as O 2-→ Fe 3+ and/or Fe 3+ -Fe 3+ pair transitions. Third, the irradiation by ultraviolet (λ=266 nm) laser source locally color the langatate sample by the creation of color centers. Origins of color centers, particularly those related to oxygen vacancies, (V O .. , 2e′) x , are discussed. And, finally, point defects changes the band gap of langatate, leading to extend the absorption to visible light regions.

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Section: Metal Ions Impuritiesmentioning

confidence: 99%

Section: Metal Ions Impuritiesmentioning

confidence: 99%

Section: Electron Color Centersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Color Origins in Langatate Crystals

Allani¹,

Batis²,

Nehari³

et al. 2017

Int. Ann. Sci.

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“…Ir contamination is considered to be the origin of the coloration in langasite crystals. 4) Therefore, the use of a different crucible for growth is needed in order to elucidate if Ir traces affect the intrinsic properties of CTGS crystals. Furthermore, the influence of oxygen partial pressure during growth on the properties of CTGS has not been investigated so far, mainly due to the use of Ir crucibles, which critically limit the maximum concentration of oxygen to a few percent.…”

Section: Introductionmentioning

confidence: 99%

Influence of growth conditions on the optical, electrical resistivity and piezoelectric properties of Ca3TaGa3Si2O14 single crystals

Vı́llora

Matsushita

et al. 2016

J. Ceram. Soc. Japan

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(CTGS) single crystals are grown by the Czochralski technique and investigated in detail for high temperature sensor applications. The influence of the oxygen partial pressure during the growth on material properties is investigated by the use of Ir crucibles, as well as Pt ones. Colorless crystals are obtained, indicating that the typical yellowish coloration of CTGS crystals is related with the use of Ir-crucibles. Colored crystals present three absorption bands at 340, 450 and 1790 nm, however, related crystal defects do not affect the electrical properties of grown crystals. Dielectric and piezoelectric properties do not vary significantly with the growth conditions. Instead, it is found that the electrical resistivity depends on the oxygen partial pressure and it is higher for CTGS crystals grown under oxygen-less atmosphere.

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The color of langatate crystals and its relationship with composition and optical properties

Кузьмичева

Kaurova

Rybakov

et al. 2012

Cryst. Res. Technol.

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Langatate crystals grown by the Czochralski method in 〈0001〉 and 〈01$ \bar 1 $1〉 directions both without subsequent annealing (from colorless to orange crystals) and with vacuum (colorless and pale‐green crystals) and air (orange crystal) annealing have been investigated by neutron diffraction, X‐ray diffraction and optical spectroscopy. The main types of point defects were compared with absorption bands: oxygen vacancies ‐ VO•• (0.35‐0.36 µm), the vacancies in the lanthanum position ‐ VLa‴ (0.29‐0.30 µm); the absorption band at 0.48‐0.49 µm is typical for the colored samples. The relationship between the X color coordinate (red component) and the oxygen contents has been obtained. The green color of the sample annealed in vacuum is due to the presence of Ta+3 ions in the La(Ta3+,Ga)O3 phase that has the structural and geometric agreement with langatate structure. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The effect of growth atmosphere and Ir contamination on electric properties of La3Ta0.5Ga5.5O14 single crystal grown by the floating zone and Czochralski method

Cited by 32 publications

References 12 publications

Color Origins in Langatate Crystals

Color Origins in Langatate Crystals

Influence of growth conditions on the optical, electrical resistivity and piezoelectric properties of Ca<sub>3</sub>TaGa<sub>3</sub>Si<sub>2</sub>O<sub>14</sub> single crystals

The color of langatate crystals and its relationship with composition and optical properties

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