Anti-phase boundaries and phase transitions in titanite; an X-ray diffraction study

University of Cambridge, Department of Earth Sciences, Cambridge, United Kingdom

X-ray diffraction rocking curves of titanite, CaTiSiO ₅ , were measured using a novel high-resolution diffractometer. Three Bragg reflections were recorded as a function of temperature and their profiles analyzed in terms of a Gaussian Bragg peak and a diffuse scattering component with an overall Lorentzian shape. The temperature dependence of the Gaussian intensities of the rocking peaks of superstructure reflections, hkl with k+l odd, scale with the long-range order parameter as I infinity Q ² infinity [T-T _c ] (super 2beta ) , where beta = 0.14(1) is the effective order parameter exponent. The diffuse scattering intensity changes little with temperature at Tc -20 K. Strong diffuse scattering is found at T>T _c with centers of their Lorentzian diffraction profiles shifted by Delta omega nearly equal 0.5 degrees with respect to the position of the equivalent Bragg peak. A second phase transition at 825 K is confirmed and the possibility of a third transition at approximately 1150 K is discussed.

This record provided courtesy of AGI/GeoRef.

This article has been cited by other articles:

				R. P. Liferovich, R. P. Liferovich, and R. H. Mitchell SOLID SOLUTIONS OF NIOBIUM IN SYNTHETIC TITANITE Can Mineral, October 1, 2006; 44(5): 1089 - 1097. [Abstract] [Full Text] [PDF]

				R. P. Liferovich and R. H. Mitchell Crystal structure of a synthetic aluminoan tantalian titanite: a reconnaissance study Mineralogical Magazine, February 1, 2006; 70(1): 115 - 121. [Abstract] [Full Text] [PDF]

				R. Ellemann-Olesen and T. Malcherek A high-temperature diffraction study of the solid solution CaTiOSiO4-CaTiOGeO4 American Mineralogist, August 1, 2005; 90(8-9): 1325 - 1334. [Abstract] [Full Text] [PDF]

				R. P. Liferovich and R. H. Mitchell COMPOSITION AND PARAGENESIS OF Na-, Nb- AND Zr-BEARING TITANITE FROM KHIBINA, RUSSIA, AND CRYSTAL-STRUCTURE DATA FOR SYNTHETIC ANALOGUES Can Mineral, April 1, 2005; 43(2): 795 - 812. [Abstract] [Full Text] [PDF]

				S. Rath, S. Rath, M. Kunz, and R. Miletich Pressure-induced phase transition in malayaite, CaSnOSiO4 American Mineralogist, February 1, 2003; 88(2-3): 293 - 300. [Abstract] [Full Text] [PDF]

				T. Malcherek Spontaneous strain in synthetic titanite, CaTiOSiO4 Mineralogical Magazine, December 1, 2001; 65(6): 709 - 715. [Abstract] [Full Text] [PDF]

				M. Kunz, T. Arlt, and J. Stolz In situ powder diffraction study of titanite (CaTiOSiO4) at high pressure and high temperature American Mineralogist, October 1, 2000; 85(10): 1465 - 1473. [Abstract] [Full Text] [PDF]

				S. A. Hayward, J. d. Cerro, and E. K.H. Salje Antiferroelectric phase transition in titanite: Excess entropy and short range order American Mineralogist, March 1, 2000; 85(3-4): 557 - 562. [Abstract] [Full Text] [PDF]

				M. Zhang, E. K.H. Salje, T. Malcherek, U. Bismayer, and L. A. Groat DEHYDRATION OF METAMICT TITANITE: AN INFRARED SPECTROSCOPIC STUDY Can Mineral, February 1, 2000; 38(1): 119 - 130. [Abstract] [Full Text] [PDF]