Transformation in garnet from orthorhombic perovskite to LiNbO3 phase on release of pressure

Science

Volumn 275, Issue 5299, 1997, Pages 513-515

  Funamori, Nobumasa ^a   Yagi, Takehiko ^a   Miyajima, Nobuyoshi ^b   Fujino, Kiyoshi ^b  

^a UNIVERSITY OF TOKYO   (Japan)

^b HOKKAIDO UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

ENVIRONMENTAL CHEMICAL; LITHIUM DERIVATIVE; MINERAL;

ARTICLE; MINERALIZATION; PRESSURE; PRIORITY JOURNAL; STRUCTURE ANALYSIS; TRANSMISSION ELECTRON MICROSCOPY; X RAY DIFFRACTION;

GARNET; P/T CONDITIONS; PEROVSKITE; PHASE TRANSITION;

EID: 0030621124     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.275.5299.513     Document Type: Article

References (29)

1. L. G. Liu, Geophys. Res. Lett. 1, 277 (1974).
2. K. Weng, H. K. Mao, P. M. Bell, Carnegie Inst. Washington Year Book 81, 273 (1982).
3. B. O'Neill and R. Jeanloz, J. Geophys. Res. 99, 19901 (1994).
4. T. Irifune, T. Koizumi, J. Ando, Phys. Earth Planet. Inter. 96, 147 (1996).
5. S. E. Kesson, J. D. Fitz Gerald, J. M. G. Shelley, R. L. Withers, Earth Planet. Sci. Lett. 134, 187 (1995).
6. I. Ahmed-Zaïd and M. Madon, ibid. 129, 233 (1995).
7. The angle-dispersive x-ray diffraction study was carried out at BL13B2 of the National Laboratory for High Energy Physics (KEK), Japan. Monochromatized x-rays (λ = 0.4143 Å) and an imaging-plate detector [J. Miyahara et al., Nucl. Instrum. Methods A246, 572 (1986)] were used in the experiments.
8. N. V. Sovolev et al., in Kimberlites of Yakutia (field Guide Book), Sixth International Kimberlite Conference (ALMAZY Rossi-SAKHA, United Institute of Geology, Geophysics, and Mineralogy, Novosibirsk, 1995), pp. 60-73.
9. Laser light (λ = 1.06 μm) was focused to a diameter of ∼15 μm and was scanned to heat the entire sample (diameter ∼120 μm). The total heating duration was ∼60 min for both runs. Maximum temperature is expected to have been below the melting temperature, ∼3000 K (24) [A. Zerr and R. Boehler, Science 262, 553 (1993)], because neither visual observations during heating nor TEM observations on recovered samples gave any indication of melting. Also, the maximum temperature is likely to have been above ∼1800 K, because Irifune et al. (4) observed a residual garnet at 1800 K. Pressure was measured by the ruby fluorescence technique [H. K. Mao et al., J. Appl. Phys. 49, 3276 (1978)]. To reduce possible contamination, we placed a small ruby chip (diameter ∼5 μm) at the midpoint between the center and the edge of the sample to measure an average pressure. The pressure during heating is expected to have been higher than the pressure measured after heating because of thermal pressure (24). 10. The samples were ion-thinned with the use of a cooling stage to prevent thermal damage. A 200-kV JEM-2010 analytical transmission electron microscope was used. Detailed TEM observations of these and other samples are reported elsewhere (N. Miyajima et al., in preparation).
10. Laser light (λ = 1.06 μm) was focused to a diameter of ∼15 μm and was scanned to heat the entire sample (diameter ∼120 μm). The total heating duration was ∼60 min for both runs. Maximum temperature is expected to have been below the melting temperature, ∼3000 K (24) [A. Zerr and R. Boehler, Science 262, 553 (1993)], because neither visual observations during heating nor TEM observations on recovered samples gave any indication of melting. Also, the maximum temperature is likely to have been above ∼1800 K, because Irifune et al. (4) observed a residual garnet at 1800 K. Pressure was measured by the ruby fluorescence technique [H. K. Mao et al., J. Appl. Phys. 49, 3276 (1978)]. To reduce possible contamination, we placed a small ruby chip (diameter ∼5 μm) at the midpoint between the center and the edge of the sample to measure an average pressure. The pressure during heating is expected to have been higher than the pressure measured after heating because of thermal pressure (24). 10. The samples were ion-thinned with the use of a cooling stage to prevent thermal damage. A 200-kV JEM-2010 analytical transmission electron microscope was used. Detailed TEM observations of these and other samples are reported elsewhere (N. Miyajima et al., in preparation).
11. Laser light (λ = 1.06 μm) was focused to a diameter of ∼15 μm and was scanned to heat the entire sample (diameter ∼120 μm). The total heating duration was ∼60 min for both runs. Maximum temperature is expected to have been below the melting temperature, ∼3000 K (24) [A. Zerr and R. Boehler, Science 262, 553 (1993)], because neither visual observations during heating nor TEM observations on recovered samples gave any indication of melting. Also, the maximum temperature is likely to have been above ∼1800 K, because Irifune et al. (4) observed a residual garnet at 1800 K. Pressure was measured by the ruby fluorescence technique [H. K. Mao et al., J. Appl. Phys. 49, 3276 (1978)]. To reduce possible contamination, we placed a small ruby chip (diameter ∼5 μm) at the midpoint between the center and the edge of the sample to measure an average pressure. The pressure during heating is expected to have been higher than the pressure measured after heating because of thermal pressure (24). 10. The samples were ion-thinned with the use of a cooling stage to prevent thermal damage. A 200-kV JEM-2010 analytical transmission electron microscope was used. Detailed TEM observations of these and other samples are reported elsewhere (N. Miyajima et al., in preparation).
12. E. Ito and Y. Matsui, Earth Planet. Sci. Lett. 38, 443 (1978); T. Yagi, H. K. Mao, P. M. Bell, Phys. Chem. Miner. 3, 97 (1978).
13. E. Ito and Y. Matsui, Earth Planet. Sci. Lett. 38, 443 (1978); T. Yagi, H. K. Mao, P. M. Bell, Phys. Chem. Miner. 3, 97 (1978).
14. 3) heated by the YAG laser, which is known to transform to the single phase of perovskite. It is also observed in our multi-anvil experiments, in which the heating duration is 1 to 2 min at ∼1800 K, but it usually disappears by heating for 30 min or more at the same temperature.
15. The x-ray diffraction lines of the garnet are broad compared with those of the other phases, indicating the presence of unrelaxed stress. The unit cell parameter of the recovered garnet is the same as that of the starting material within experimental uncertainty. In addition, the garnet has not been observed by TEM, probably because the low-temperature part of the sample, which had been adjacent to diamonds, was removed during ion-thinning. From these observations, we believe that the garnet observed after heating is residual starting material.
16. H. K. Mao et al., J. Geophys. Res. 96, 8069 (1991); N. Funamori, T. Yagi, T. Uchida, W. Utsumi, Proc. 14th AIRAPT Conf., 791 (1994).
17. H. K. Mao et al., J. Geophys. Res. 96, 8069 (1991); N. Funamori, T. Yagi, T. Uchida, W. Utsumi, Proc. 14th AIRAPT Conf., 791 (1994).
18. L. G. Liu, Earth Planet. Sci. Lett. 31, 200 (1976); E. Ito and Y. Matsui, in High-Pressure Research: Applications in Geophysics, M. H. Manghnani and S. Akimoto, Eds. (Academic Press, New York, 1977), pp. 193-208.
19. L. G. Liu, Earth Planet. Sci. Lett. 31, 200 (1976); E. Ito and Y. Matsui, in High-Pressure Research: Applications in Geophysics, M. H. Manghnani and S. Akimoto, Eds. (Academic Press, New York, 1977), pp. 193-208.
20. K. Leinenweber, W. Utsumi, Y. Tsuchida, T. Yagi, K. Kurita, Phys. Chem. Miner. 18, 244 (1991).
21. R. D. Shannon and C. T. Prewitt, Acta. Crystallogr. B26, 925 (1969).
22. N. L. Ross, J. Ko, C. T. Prewitt, Phys. Chem. Miner. 16, 621 (1989).
23. K. Leinenweber, Y. Wang, T. Yagi, H. Yusa, Am. Mineral. 79, 197 (1994).
24. 2+.
25. J. Ko and C. T. Prewitt, Phys. Chem. Miner. 15, 355 (1988).
26. T. Irifune, Nature 370, 131 (1994).
27. B. O'Neill and R. Jeanloz, Geophys. Res. Lett. 17, 1477 (1990).
28. D. L. Heinz and R. Jeanloz, J. Geophys. Res. 92, 11437 (1987).
29. We thank O. Shimomura, T. Kikegawa, K. Aoki, H. Fujihisa, H. Yamawaki, T. Kondo, T. Uchida, and M. Yamakata for support of the experiments and R. Jeanloz, M. Akaogi, and C. T. Prewitt for helpful comments. The garnet sample was provided by T. Watanabe and A. Agashev. X-ray experiments were carried out at KEK (96S02). N.F. and N.M. were supported by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists.