Cr+3 Distribution in Al1 and Al2 Sites of Alexandrite (BeAl2O4: Cr3+) Induced by Annealing, Investigated by Optical Spectroscopy

Neilo M. TRINDADE, Rosa M. F. SCALVI, Luis V. A. SCALVI

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DOI: 10.4236/epe.2010.21004                

Abstract

In order to investigate optical properties of alexandrite, the present work deals with the influence of thermal annealing on optical absorption and luminescence spectra of natural samples. The exposure time to heat treatment at 1000oC is taken into account. Possible migration of Cr3+ ions from Al1 (inversion site) to Al2 (reflection site) is detected. Sample composition is obtained through Scanning Electron Microscopy (SEM) measurements and points to a rearrangement of Cr+3 and Fe3+ ions in the alexandrite crystalline structure, un-der thermal annealing influence. This feature may be used to control the optical properties of natural alexan-drite, which can be associated to the observed laser emission effect.

Keywords

A. oxides, D. optical properties, D. defects

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	J. C. Walling, O. G. Peterson, H. P. Jenssen, R. C. Morris, and E. W. O′Dell, “Tunable alexandrite lasers,” IEEE Journal of Quantum Electronics, Vol. QE-16, pp. 1302– 1314, 1980.
[2]	J. C. Walling, D. F. Heller, H. Samelson, D. J. Harter, A. J. A. Pete, and R. C. Morris, “Tunable alexandrite lasers: development and performance,” IEEE Journal of Quantum Electronics, Vol. QE-21, pp 1568–1581, 1985.
[3]	L. Li, T. Kono, W. F. Groff, H.M. Chan, Y. Kitazawa, and N. J. Nozaki, “Comparison study of a long-pulse pulsed dye laser and a long-pulse pulsed alexandrite laser in the treatment of port wine stains,” Journal of Cosmetic and Laser Therapy, Vol. 10, pp. 1472–1476, 2008.
[4]	N. Bouzari, H. Tabatabai, Z. Abbasi, and A. Frios, “Laser hair removal: Comparison of long-pulsed Nd: YAG, ‘Long-pulsed alexandrite, and long-pulsed Diode Lasers’,” Dermatologic Surgery, Vol. 30, pp. 498–502, 2008.
[5]	M. Landthaler and U. Hohenleutner, “Laser therapy of vascular lesions photodermatology,” Photoimmunology & Photomedicine, Vol. 22, pp. 324–332, 2006.
[6]	S. C. Collins, T. D. Wilkerson, V. B. Wickwar, D. Rees, J. C. Walling, and D. F. Heller, “The alexandrite ring laser: A spectrally narrow lidar light source for atmospheric fluorescence and absorption observations in Advances in atmospheric remote sensing with Lidar,” Edited by A. Ansmann, R. Neuber, P. Rairoux, and U. Wandinger, Springer Verlag, Berlin, pp. 577–580, 1997.
[7]	S. U. Weber, M. Grodzicki, W. Lottermoser, G. J. Red- hammer, G. Tippelt, J. Ponahlo, and G. Amthauer, “Fe Mossbauer spectroscopy, X-ray single-crystal diffrac- tometry, and electronic structure calculations on natural alexandrite,” Physics and Chemistry of Minerals, Vol. 34, pp. 507–515, 2007.
[8]	V. I. Solomonov, S. G. Mikhailov, and A. I. Lipchak, “Impurity luminescence of alexandrite crystals,” Journal of Applied Physics, Vol. 69, pp. 423–429, 2002.
[9]	R. M. F. Scalvi, M. S. Li, and L. V. A. Scalvi, “Thermal annealing-induced electric dipole relaxation in natural alexandrite,” Physics and Chemistry Minerals, Vol. 31, pp. 733–737, 2005.
[10]	C. F. Cline, R. C. Morris, M. Dutoit, and P. J. Harget, “Physical properties of BeAl2O4 single crystals,” Journal of Materials Science, Vol. 14, pp. 941–944, 1979.
[11]	G. V. Bukin, A. V. Eliseev, V. N. Matrosov, V. P. Solntsev, E. I. Kharchenko, and E. G. Tsvetjov, “The growth and examination of optical properties of gem alexandrite,” Proceedings of the XI IMA Meeting, Novosibirsk, pp. 317–328, 1980.
[12]	J. A. Hernandez, W. K. Cory, and J. O. Rubio, “A non destructive method for determining the Eu2+ concentration in the alkali chlorides,” Japanese Journal of Applied Physics, Vol. 18, pp. 533–538, 1979.
[13]	M. J. Weber and T. E. Varitimos, “Optical spectra and relaxation of Cr3+ ion in YAlO3,” Journal of Applied Physics, Vol. 45, pp. 810–816, 1974.
[14]	J. Xu, K. Shi, G. Xiong, and X. Xu, “The vibrational relaxation processes in BeAl2O4:Cr3+”, Journal of Luminescence, Vol. 40 & 41, pp. 611–612, 1988.
[15]	A. E. Underhill and D. E. Billing, “Calculation of the Racah parameter B for Nickel (II) and cobalt (II) compounds,” Nature, Vol. 210, pp. 834–835, 1966.
[16]	R. C. Powell, L. Xi, X. Gang, and G. J. Quarles, “Spectroscopic properties of alexandrite crystals,” Physical Review B, Vol. 32, pp. 2788–2797, 1985.
[17]	A. B. Suchocki, G. D. Gilliland, R. C. Powell, and J. M Bowen, “Spectroscopy properties of alexandrite crystals II,” Journal of Luminescence, Vol. 37, pp. 29–37, 1987.
[18]	F. Hassan and A. El-Rakhawy, “Chromium III centers in synthetic alexandrite,” American Mineralogist, Vol. 59, pp. 159–165, 1974.
[19]	S. K. Pan and X. G. Wang, “Growth of laser crystal alexandrite,” Crystal Research and Technology, Vol. 29, pp. k31–k35, 1994.
[20]	P. Fabeni, G. P. Pazzi, and L. Salvini, “Impurity centers for tunable lasers in the ultraviolet and visible regions,” Journal of Physics and Chemistry of Solids, Vol. 52, pp. 299–317, 1991.
[21]	R. M. F. Scalvi, M. S. Li, and L. V. A. Scalvi, “Annealing effects on optical properties of natural alexandrite,” Journal of Physics: Condensed Matter, Vol. 15, pp. 7437– 7443, 2003.
[22]	H. Rager, A. Bakhshand-Khiri, and K. Schmetze, “Investigation of the intracrystalline Cr3+ distribution in natural and synthetic alexandrites,” N. Jb. Miner. Mh, Vol. 2 , pp. 545–557, 1998.
[23]	B. K. Sevast’yanov, “Excited-state absorption spectroscopy of crystal dopede with Cr3+, Ti3+, and Nd3+ ions, review,” Crystallography Reports, Vol. 48, pp. 989–1011, 2003.
[24]	R. M. F. Scalvi, L. O. Ruggiero, and M. S. Li, “Influence of annealing on X-Ray diffraction of natural alexandrite,” Powder Diffraction, Vol. 17, pp. 135–138, 2002.