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Growth of BaxSr1-xSO4 nano-steps on barite (001) face

YuHang, Chen and Asenjo Barahona, Agustina and Sánchez Pastor, Nuria and Fernández Díaz, Lourdes and Gómez Herrero, Julio and Pina Martínez, Carlos Manuel (2007) Growth of BaxSr1-xSO4 nano-steps on barite (001) face. Surface science, 601 . pp. 381-389. ISSN 0039-6028

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Abstract

Crystal growth has been promoted in the fluid cell of an Atomic Force Microscope (AFM) by passing Ba–Sr–SO4 aqueous solutions
over barite (001) cleavage surfaces. Steps advance in structural continuity with the original barite (001) surfaces and two-dimensional
nucleation occurs preferentially on the newly-formed terraces. The terraces are, on average, 7.5% lower than pure barite terraces. Since
the ionic radius of Sr2+ is smaller that the ionic radius of Ba2+, the reduction of terrace height is consistent with an extensive incorporation
of Sr2+ into the barite structure. Therefore, it can be considered that the newly-formed terraces have compositions corresponding
to terms of the BaxSr1xSO4 solid solution. A non-linear dependence of step rate on [SrSO4] concentration in the solution (and therefore
on supersaturation) has been found. The growth behaviour has been discussed by considering both the physicochemical properties of the
BaxSr1xSO4 solid solution–aqueous solution (SS–AS) system and a kinetic-based step growth model.

Item Type:Article
Uncontrolled Keywords:Atomic force microscopy; Barite; Celestite; Solid solution; Crystal growth
Subjects:Sciences > Geology > Crystallography
ID Code:14051
Deposited On:16 Dec 2011 10:39
Last Modified:16 Dec 2011 10:39

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