- Access by Xinjiang University
Ferroelectricity in the Ilmenite Structure
Phys. Rev. 87, 5 – Published 1 July, 1952
DOI: https://doi.org/10.1103/PhysRev.87.5
Abstract
The ferroelectricity of the ilmenite structure minerals lithium tantalate and lithium niobate is studied theoretically, using the method recently introduced by Slater for barium titanate. The metal ions are assumed to move in a potential which has small quartic terms as well as the usual quadratic terms, all satisfying the appropriate crystal symmetry requirements. This results in a slight dependence of the ionic-displacement polarizability of each metal ion on both the temperature and the polarization of the crystal. The local electric field strength is computed exactly for each ion by Ewald's method, and the internal field constants are given for a number of positions in a rhombohedral unit cell of axial angle . The polarizabilities can be estimated from other crystal polarization data, leading to a spontaneous polarization below the upper Curie temperature of microcoulombs (without electromechanical correction). Whereas in barium titanate all dipole moments are in the direction of the resultant polarization, it is found here that the lower crystal symmetry results in sizeable components of the oxygen dipole moments perpendicular to the total polarization, but these last components produce a large field in the direction of the polarization at other ionic positions.
References (21)
- J. Valasek, Phys. Rev. 17, 475 (1921)
- G. Busch and P. Scherrer, Naturwiss. 23, 737 (1935)
- von Hippel, Breckenridge, Chesley, and Tisza, Ind. Eng. Chem. 38, 1097 (1946)
- B. T. Matthias and J. P. Remeika, Phys. Rev. 76, 1886 (1949)
- J. C. Slater, Phys. Rev. 78, 748 (1950)
- E. A. Wood (private communication)
- H. A. Miers, Mineralogy (Macmillan Company, New York, 1929), second edition, p. 77
- W. H. Zachariasen, Skrifter Norske Videnskans-Akad. Oslo. I. Mat.-Naturv. Klasse No. 4 (1928) [6]
- R. W. G. Wyckoff, Crystal Structures (Interscience Publishers, Inc., New York, 1948), first edition, pp. V, a5 and V A, 6
- C. Gottfried and F. Schossberger, Strukturbericht (Akademische Verlagsgesellschaft, Leipzig, 1937), first edition, Vol. 3, p. 379
- Linus Pauling, The Nature of the Chemical Bond (Cornell University Press, Ithaca, New York, 1948), second edition, p. 346
- W. Voigt, Lehrbuch der Kristallphysik (B. G. Teubner, Leipzig, Germany, 1910), first edition, p. 750
Omitted endnote
- P. P. Ewald, Ann. Phys. 64, 253 (1921)
- M. Born and M. G. Mayer, Handbuch der Physik (Verlag. Julius Springer, Berlin, Germany, 1933), second edition, Vol. 24, p. 710
- Tables of Probability Functions (Government Printing Office, Washington, D. C., 1941), first edition, Vol. I
- "Ferroelectricity in the Ilmenite Structure"(Technical Report No. 1, Solid-State and Molecular Theory Group, Massachusetts Institute of Technology)
- K. Fajans and G. Joos, Z. Physik 23, 1 (1924)
- L. Pauling, Proc. Roy. Soc. (London) A411, 191 (1927)
- A. Guentherschulze and F. Keller, Z. Physik 75, 78 (1932)
- W. L. Bragg, The Crystalline State (G. Bell and Sons, London, 1949), first edition, Vol. I, p. 182