Temperature-induced phase transitions for stuffed tridymites SrGa 2 O 4 and CaGa 2 O 4

Jiang, Fuwei; Jiang, Pengfei; Yue, Mufei; Gao, Wenliang; Cong, Rihong; Yang, Tao

doi:10.1016/j.jssc.2017.07.024

Cited by 11 publications

(7 citation statements)

References 24 publications

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“…Temperature-induced γ-to-β SrGa 2 O 4 phase transition was reported to be 1200 °C . Phase-pure samples with γ-SrGa 2 O 4 -structures could be prepared at low temperatures for 0.67 < x < 1.0 (region VI in Figure ), while the β-SrGa 2 O 4 -type phase can be only observed as one component in the biphasic region for 0.8 < x < 1.0 (see Figures d and S5).…”

Section: Resultsmentioning

confidence: 94%

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Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca_1–xSr_xGa₂O₄

et al. 2021

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Stuffed tridymites AM 2 O 4 composed of a condensed MO 4 -tetrahedra-based framework have been widely investigated due to their structural diversity and rich physical properties. Herein, the strategy of stuffing mixed Ca 2+ and Sr 2+ cations into the [Ga 2 O 4 ] 2− framework in (Ca 1−x Sr x )Ga 2 O 4 (CSGO, 0 ≤ x ≤ 1) is utilized to manipulate the phase formation behavior with different structure types at particular annealing temperatures. Five derivatives, including αand β-CaGa 2 O 4 , βand γ-SrGa 2 O 4 , and new CSGO-type structures, were observed. The distinctive feature of the CSGO-structure is the coexistence of UUDDUD-and UDUDUD-type six-membered rings, where U (up) and D (down) denote the orientations of GaO 4 -tetrahedra with respect to the plane grids, in a ratio of 2:1. Single-phase α-Ca 1−x Sr x Ga 2 O 4 (x < 0.2) and γ-Ca 1−x Sr x Ga 2 O 4 (x > 0.67) could be obtained at low temperatures. Biphasic regions, including α-Ca 1−x Sr x Ga 2 O 4 /CSGO (0.2 ≤ x ≤ 0.67), γ-Ca 1−x Sr x Ga 2 O 4 /CSGO (0.67 < x ≤ 0.8), and β-Ca 1−x Sr x Ga 2 O 4 /CSGO (0.8 < x < 1), were observed at the intermediate temperature region and evolve irreversibly into the CSGO single-phase region upon elevating the temperature. Moreover, the structure−property relationship of the new CSGO-phase was further studied by doping coordinationsensitive Bi 3+ activators to advance the development and applications of stuffed tridymites.

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Section: Resultsmentioning

confidence: 94%

“…There exist two polymorphs of CaGa 2 O 4 at ambient pressure. α-CaGa 2 O 4 is stable below 1350 °C, and it is supposed to form β-CaGa 2 O 4 at 1350 °C . Experimentally, it is difficult to obtain phase-pure β-CaGa 2 O 4 because the phase transition temperature is quite close to its melting point.…”

Section: Resultsmentioning

confidence: 99%

Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca_1–xSr_xGa₂O₄

et al. 2021

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“…The luminophore was synthesized using the solid-state method in a high-temperature furnace in an air atmosphere at 1250 °C for 18 h. These temperature and time parameters were selected based on experimental X-ray diffraction data on specimens synthesized under different conditions. Detailed description of α-CaGa 2 O 4 and β-CaGa 2 O 4 polymorphic phase formation in the 1050-1350 °C range was reported earlier [7]. The 1250-1350 °C range is the optimum one for synthesizing the CaGa 2 O 4 phase at normal atmospheric pressure in the presence of oxygen gas.…”

Section: Methodsmentioning

confidence: 85%

“…The main unexcited level 2 F 7/2 consists of four Stark sublevels (1,2,3,4) and the excited level 2 F 5/2 is split into three sublevels (5,6,7). Arrows show potential electron transitions with energy absorption or release.…”

Section: Resultsmentioning

confidence: 99%

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IR luminescence of CaGa 2O 4 : Yb 3+ excited by 940 and 980 nm radiation

Mar’ina¹,

Vorob'ev²,

Mar’in³

2020

MoEM

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Existing calcium gallate CaGa2O4 based luminescent materials radiating in visible IR region have been reviewed. IR luminophores have been studied but slightly but their practical implementation is of interest. CaGa2O4 specimens activated with Yb3+ rare-earth ions have been synthesized using the solid-state method. The structure and luminescent properties of CaGa2O4 : Yb3+ have been studied. CaGa2O4 : Yb3+ excitation with 940 and 980 nm radiation generates luminescence in the 980–1100 nm region. Data on the electron level structure in Yb3+ ions suggest that the excitation and luminescence occur directly in the Yb3+ ions with only a passive role of the base lattice. The luminescence spectra contain three peaks at 993, 1025 and 1080 nm. These luminescence peaks are caused by electron optical transitions from excited to main state in Yb3+ ions. 993 nm band luminescence intensity has been studied as a function of Yb3+ activator ions concentration. Introduction of Na+ ions into the luminophore increases IR luminescence intensity. Optimum (Ca1-x-yYbxNay)Ga2O4 luminophore composition has been suggested at which the 993 nm luminescence intensity is the highest.

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Exploring crystal-field splittings of Eu3+ ions in γ- and β-SrGa2O4

Liu

Wang

et al. 2019

Journal of Luminescence

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Temperature-induced phase transitions for stuffed tridymites SrGa 2 O 4 and CaGa 2 O 4

Cited by 11 publications

References 24 publications

Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca_1–xSr_xGa₂O₄

Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca_1–xSr_xGa₂O₄

IR luminescence of CaGa 2O 4 : Yb 3+ excited by 940 and 980 nm radiation

Exploring crystal-field splittings of Eu3+ ions in γ- and β-SrGa2O4

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Temperature-induced phase transitions for stuffed tridymites SrGa 2 O 4 and CaGa 2 O 4

Cited by 11 publications

References 24 publications

Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca1–xSrxGa2O4

Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca1–xSrxGa2O4

IR luminescence of CaGa 2O 4 : Yb 3+ excited by 940 and 980 nm radiation

Exploring crystal-field splittings of Eu3+ ions in γ- and β-SrGa2O4

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Product

Resources

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Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca_1–xSr_xGa₂O₄

Structural Diversity and Incompatibility Induced Complex Phase Formation Behavior in the Stuffed Tridymites Ca_1–xSr_xGa₂O₄