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References
Morelli, A. D., Dziewonski, A. M. & Woodhouse, J. H. Anisotropy of the inner core inferred from PKIKP travel times. Geophys. Res. Lett. 13, 1545–1548 (1986).
Woodhouse, J. H., Giardini, D. & Li, X. D. Evidence for inner core anisotropy from free oscillations. Geophys. Res. Lett. 13, 1549–1552 (1986).
Creager, K. C. Anisotropy of the inner core from differential travel times of the phases PKP and PKIKP. Nature 356, 309–314 (1992).
Tromp, J. Support for anisotropy of the Earth's inner core from free oscillations. Nature 366, 678–681 (1993).
Shearer, P. Constraints on inner core anisotropy from PKP(DF) travel times. J. Geophys. Res. 99, 19647–19659 (1994).
Su, W. & Dziewonski, A. M. Inner core anisotropy in three dimensions. J. Geophys. Res. 100, 9831–9852 (1995).
7. Song, X. Anisotropy in central part of inner core. J. Geophys. Res. 101, 16089–16097 (1996).
Porter, D. A. & Easterling, K. E. Phase Transformations in Metals and Alloys(Chapman &Hall, London, (1992)).
Chalmers, B., Principles of Solidification(Wiley, New York, (1964)).
Glatzmaier, G. A. & Roberts, P. H. Dynamo theory then and now. Int. J. Eng. Sci.(in the press).
Cormier, V. F. Inner core structure inferred from body waveforms. Eos 75, 67 (1994).
Souriau, A. & Romanowicz, B. Anisotropy in inner core attenuation: a new type of data to constrain the nature of the solid core. Geophys. Res. Lett. 23, 1–4 (1996).
Wenk, H. R., Takeshita, T., Jeanloz, R. & Johnson, G. C. Development of texture and elastic anisotropy during deformation of hcp metals. Geophys. Res. Lett. 15, 76–79 (1988).
Karato, S. I. Inner core anisotropy due to the magnetic field-induced preferred orientation of iron. Science 262, 1708–1711 (1993).
Stixrude, L. & Cohen, R. E. High-pressure elasticity of iron and anisotropy of Earth's inner core. Science 267, 1972–1975 (1995).
Stacey, F. Physics of the Earth(Brookfield, Brisbane, (1992)).
Yoshida, S., Sumita, I. & Kumazawa, M. Growth model of the inner core coupled with the outer core dynamics and the resulting elastic anisotropy. J. Geophys. Res. 101, 28085–28103 (1996).
Rutter, J. W. in Liquid Metals and Solidification(ed. Maddin, R.) 243–262 (American Society of Metals, Cleveland, (1958)).
Haasen, P. Physical Metallurgy(Cambridge Univ. Press, (1978)).
Barrett, C. & Massalski, T. B. Structure of Metals(Pergamon, New York, (1980)).
Sherman, D. M. Stability of possible Fe–FeS and Fe–FeO alloy phases at high pressure and the composition of the Earth's core. Earth Planet. Sci. Lett. 132, 87–98 (1995).
Fearn, D. R., Loper, D. E. & Roberts, P. H. Structure of the Earth's inner core. Nature 292, 232–233 (1981).
Esbensen, K. H. & Buchwald, V. F. Planet(oid) core crystallization and fractionation-evidence from the Apaghlik mass of the Cape York iron meteorite shower. Phys. Earth. Planet. Inter. 29, 218–232 (1982).
Bergman, M. I., Fearn, D. R., Bloxham, J. & Shannon, M. Convection and channel formation in solidifying Pb–Sn alloys. Metallurgical Transactions A 28, 859–866 (1997).
Bergman, M. I. & Fearn, D. R. Chimneys on the Earth's inner–outer boundary? Geophys. Res. Lett. 21, 477–480 (1994).
Worster, M. G. Natural convection in a mushy layer. J. Fluid Mech. 224, 335–359 (1991).
Loper, D. E. Structure of the inner core boundary. Geophys. Astrophys. Fluid Dyn. 25, 139–155 (1983).
Doornbos, D. J. The anelasticity of the inner core. Geophys. J. R. Astron. Soc. 38, 397–415 (1974).
Saxena, S. K.et al. Synchrotron X-ray study of iron at high pressure and temperature. Science 269, 1703–1704 (1995).
Simmons, G. & Wang, H. Single Crystal Elastic Constants and Calculated Aggregate Properties(MIT Press, Cambridge, MA, (1971)).
McSkimin, H. J. Ultrasonic measurement techniques applicable to small solid specimens. J. Acoust. Soc. Am. 22, 413–418 (1950).
Roth, W. Scattering of ultrasonic radiation in polycrystalline metals. J. Appl. Phys. 19, 901–910 (1948).
Mason, W. P. & McSkimin, H. J. Energy losses of sound waves in metals due to scattering and diffusion. J. Appl. Phys. 19, 940–946 (1948).
Acknowledgements
I thank K. Bishop (Matec Instruments) and B. Li for assistance with the ultrasonic measurements; J. Bloxham, W. Dunbar, D. Fearn, C. Francis, W. Kuang, H. Ma, R. O'Connell, M. Shannon, F. Spaepen, J. Tromp, and especially S. Zatman for suggestions; G. Glatzmaier and S. Yoshida for providing preprints; and J. Bloxham, supported by the David and Lucile Packard Foundation and the NSF, and Harvard University, for providing facilities. This work was supported by a Cottrell College Science Award of the Research Corporation.
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Bergman, M. Measurements of electric anisotropy due to solidification texturing and the implications for the Earth's inner core. Nature 389, 60–63 (1997). https://doi.org/10.1038/37962
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DOI: https://doi.org/10.1038/37962
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