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Materials Data on BaLaGa3O7 by Materials Project

BaLaGa3O7 crystallizes in the orthorhombic Cmm2 space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.04 Å. La3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of La–O bond distances ranging from 2.37–3.01 Å. There are three inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four O2- atoms to form corner-sharing GaO4 tetrahedra. There is two shorter (1.86 Å) and two longer (1.89 Å) Ga–O bond length. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form corner-sharing GaO4 tetrahedra. There is one shorter (1.83 Å) and three longer (1.88 Å) Ga–O bond length. In the third Ga3+ site, Ga3+ is bonded to four O2- atoms to form corner-sharing GaO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.82–1.91 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two equivalent Ga3+ atoms. In the second O2- site, O2- is bonded to two equivalent La3+ and two equivalent Ga3+ atoms to form a mixture of distorted corner and edge-sharing OLa2Ga2 tetrahedra. In the third O2- site, O2- is bonded to one Ba2+, two equivalent La3+, and one Ga3+ atom to form a mixture of distorted corner and edge-sharing OBaLa2Ga tetrahedra. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, one La3+, and one Ga3+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, one La3+, and two Ga3+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one La3+, and two Ga3+ atoms.

36 MATERIALS SCIENCE↗

Spectroscopic properties and rate equation model of Er doped BaLaGa3O7 crystals

Highlights: • We grew Er{sup 3+} activated BaLaGa{sub 3}O{sub 7} crystal for usage in mid-infrared laser. • The change of Er{sup 3+} doping concentration had significant effect on the fluorescence properties. • The best doping concentration of Er{sup 3+} should be maintained at 10–15at% to obtain 2.7 μm output. • We built and discussed the rate equation model according to the energy transfer diagram. - Abstract: Single crystals of pure and Er{sup 3+} doped BaLaGa{sub 3}O{sub 7} were grown successfully by the Czochralski technique. The absorption spectra, emission spectra including up-conversion, near-infrared and mid-infrared fluorescence spectra, as well as the fluorescence decay curves were measured at room temperature. The optical parameters of absorption and emission cross sections, the fluorescence lifetimes were evaluated and compared. Based on the Judde-Ofelt theory, Judde-Ofelt parameters such as the fluorescent branching ratios, the spontaneous transition probabilities and the radiative lifetimes were calculated. According to the energy transfer diagram, the rate equation model was built and discussed. In summary, Er{sup 3+}: BaLaGa{sub 3}O{sub 7} crystal is attractive and significant as laser gain material for realization of ∼2.7 μm laser output.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗