Publication: ESR study of spin-Hamiltonian parameters and crystal field energy levels for the low C<inf>3</inf>symmetry Fe<sup>3+</sup>center in green sapphire crystals and powder
Issued Date
2007-02-10
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ISSN
02179849
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2-s2.0-33947121332
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Mahidol University
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SCOPUS
Bibliographic Citation
Modern Physics Letters B. Vol.21, No.4 (2007), 225-236
Suggested Citation
P. Limsuwan, N. Udomkan, P. Winotai ESR study of spin-Hamiltonian parameters and crystal field energy levels for the low C<inf>3</inf>symmetry Fe<sup>3+</sup>center in green sapphire crystals and powder. Modern Physics Letters B. Vol.21, No.4 (2007), 225-236. doi:10.1142/S0217984907012505 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/25133
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Title
ESR study of spin-Hamiltonian parameters and crystal field energy levels for the low C<inf>3</inf>symmetry Fe<sup>3+</sup>center in green sapphire crystals and powder
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Abstract
In this report, Fe3+impurity ions present in green sapphire (Al3O3) were studied experimentally, by heating a light green sapphire in flowing oxygen atmosphere for 12 h from 1200, 1300, 1400, 1500 and 1600°C, respectively. Electron spin resonance (ESR) spectra in X-band (∼9.45 GHz) were recorded by mounting the crystal with the c-axis perpendicular (θ = 90°) to the magnetic field direction. The spectra were recorded and simulated by a numerical diagonalization of spin Hamiltonian matrix in the range from 0 to 180 degrees for every 15 degrees of rotation angle (φ). In our case, only the last two sets of peaks strongly depend on the rotation angle (φ), and each exhibits C3symmetry due to two magnetically inequivalent Fe3+sites in the corundum structure. For polycrystalline ESR spectra, seven main Fe3+ESR absorption peaks occur at the resonance magnetic fields of 100.20, 310.24, 486.80, 525.00, 550.60, 761.00 and 777.00 mT respectively. Specifically, ESR signals show that the number of paramagnetic Fe3+ions increase roughly linearly with the heat treating temperature, having the Fe3+/FeRT3+ratio ∼1.41 at 1600°C. © World Scientific Publishing Company.