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arXiv · 2201.07477

Raman and photoluminescence spectroscopic studies on structural disorder in oxygen deficient Gd2Ti2O7-d single crystals

M. Suganya·K. Ganesan·P. Vijayakumar·Amirdha Sher Gill·S. K. Srivastava·Ch. Kishan singh·R. M. Sarguna·P. K. Ajikumar·S. Ganesamoorthy
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Abstract

We report on Raman and photoluminescence spectroscopic studies on oxygen vacancy induced structural disorder in Gd2Ti2O7-d single crystals grown by optical floating zone technique under argon atmosphere. The oxygen vacancies in Gd2Ti2O7-d wafers decrease with thermal annealing in an air atmosphere. The full width at half maximum of X-ray diffraction rocking curve decreases from 245 to 157 arc-second and the optical transmittance increases from 23 to 87 % (at 1000 nm) upon post growth thermal annealing. Raman spectroscopic studies reveal a monotonic increase in intensity of O-Gd-O (Eg) and Ti-O (A1g) stretching modes with thermal annealing. Since these modes are associated with modulation of oxygen x parameter which is sensitive to Ti-O octahedron distortion, the increase in Raman intensity indicates an improvement in structural ordering of oxygen sub-lattice in Gd2Ti2O7-d. Moreover, the photoluminescence studies also corroborate the Raman analysis in terms of reduction of structural defects associated with oxygen vacancies as a function of thermal annealing. This study demonstrates the effectiveness of using Raman spectroscopy to probe the structural disorder in Gd2Ti2O7-d crystals.

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M. Suganya, K. Ganesan, P. Vijayakumar, Amirdha Sher Gill, S. K. Srivastava, Ch. Kishan singh, R. M. Sarguna, P. K. Ajikumar, S. Ganesamoorthy. 2022-01-19. Raman and photoluminescence spectroscopic studies on structural disorder in oxygen deficient Gd2Ti2O7-d single crystals. https://doi.org/10.1002/crat.202100287

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