Refinement of the crystal structures of the La3Ta0.5Ga5.5O14 and La3Nb0.5Ga5.5O14 compounds

Dudka, A. P.; Mill, B. V.; Pisarevsky, Yu. V.

doi:10.1134/s106377450904004x

Cited by 23 publications

(18 citation statements)

References 18 publications

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“…In the model proposed for La 3 Ta 0.5 Ga 5.5 O 14 and La 3 Nb 0.5 Ga 5.5 O 14 in [7], the dis placements of the first and third cations in the 3e and 3f sites were described by a fourth rank tensor. This model is labeled as 4242222 [9].…”

Section: Resultsmentioning

confidence: 99%

“…The maximum difference in the coordinates determined in [4] and in the present study is 6σ. The shifts of the coordinates reported in [4] are attributed to the use of low resolution X ray diffraction data, which was analyzed in [7].…”

Section: Resultsmentioning

confidence: 99%

“…Systematic accurate studies of the crystal structures of the langasite family based on high resolution X ray diffraction data collected under various experimental conditions were started in [7]. The goal was to deter mine the structural features responsible for the physi cal (in particular, piezoelectric) properties of these crystals.…”

Section: Introductionmentioning

confidence: 99%

“…Empha sis was given to determining the atomic coordinates and atomic displacement parameters (ADP), while taking into account the anharmonic term [7,8], which were reproduced in repeated experiments. The crystal structures of SGG and Sr 3 TaGa 3 Si 2 O 14 (STGS) [9] were compared.…”

Section: Introductionmentioning

confidence: 99%

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Crystal-structure refinement of Sr3Ga2Ge4O14

Dudka

Mill

2012

Crystallogr. Rep.

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The accurate X ray diffraction study of a Sr 3 Ga 2 Ge 4 O 14 crystal was performed based on two X ray diffraction data sets collected on a diffractometer equipped with a CCD area detector (a = 8.2776(2), c = 5.0415(1) Å, sp. gr. P321, Z = 1, R/wR = 0.78/0.69%, 3645 independent reflections). The structure of Sr 3 Ga 2 Ge 4 O 14 is characterized by the presence of two mixed cation sites, which is accompanied by the anhar monic motion not only of cations, but also of two oxygen atoms in general positions. The structures and elec tromechanical characteristics of Sr

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crystal-structure refinement of Sr3Ga2Ge4O14

Dudka

Mill

2012

Crystallogr. Rep.

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“…It does not show a phase transition from room temperature to its melting point. Dudka et al 3 reported that Langatate crystal grown under 10% O 2 / N 2 atmosphere condition showed 0.523:0.477 ratio for Ga and Ta on the 1a octahedral site. The LTG crystal belongs to the P321 space group, Ca 3 Ga 2 Ge 4 O 14 -type disordered structure like other langasite ͑La 3 Ga 5 SiO 14 , LGS͒ family materials such as Sr 3 Ga 2 Ge 4 O 14 and La 3 Nb 0.5 Ga 5.5 O 14 but its crystal structure differs from ordered structure e.g., Sr 3 TaGa 3 Si 2 O 14 , Ca 3 TaAl 3 Si 2 O 14 , etc.…”

Section: Introductionmentioning

confidence: 99%

First principles calculation of La3Ta0.5Ga5.5O14 crystal with acceptor-like intrinsic point defects

Chung

Yaokawa

Mizuseki

et al. 2010

Journal of Applied Physics

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Langatate ͑La 3 Ta 0.5 Ga 5.5 O 14 , LTG͒ single crystal has been one of the promising candidate piezoelectric materials in high temperature applications because of its structural stability at high temperature. However, it has been reported that compositions of LTG grown by the Czochralski method deviates from the ideal stoichiometry to Ta-poor and Ga-rich material. In this work, to elucidate the energetic stability of defects and their influences on electronic properties, defect formation energies, and electronic properties were calculated for perfect and defective LTG crystals by using first-principles calculations. The results with oxygen-rich assumption showed that Ga substitution on Ta site and Ta vacancy were the most energetically stable defects among various acceptor-like defects under low and high Fermi energy region, respectively. The most stable cation vacancy V Ta ЈЈЈЈЈ could affect the electronic and optical properties of the LTG crystal, as the band gap of a crystal with V Ta ЈЈЈЈЈ has a smaller gap than other defects.

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