Molecular dynamics studies of solid solutions based on ATiO3 type compounds

• Grant number: 08/10833-1
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): March 01, 2009
• Effective date (End): September 30, 2010
• Field of knowledge: Physical Sciences and Mathematics - Physics
• Principal Investigator: José Pedro Rino
• Grantee: James Alves de Souza
• Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Atomistic simulations were performed by Molecular Dynamics to describe compounds of ATiO3 (SrTiO3 and CaTiO3), in my Master Science work funded by FAPESP - Process No. 06/57581-1 to be finished soon. The interatomic potential proposed accurately reproduces structural properties, such as the phase transitions, and dynamic, as density of vibrational modes of these materials. Given the good results obtained, studies will be conducted to study solid solutions of the sort A(1-x)B(x)TiO3, with A and B being one of the elements Ca, Sr, Pb and Ba, by the interpolation of the interatomic potential of the titanates already established. Using the same method, composites such as ATiO3 | BTiO3 | ATiO3 (A, B = Ca, Sr, Ba and Pb) will be studied to verify the effects of the physical properties of these materials by the presence of interfaces. Initially, handling of interfaces will be carry out in a matrix of a material of the same substance, simulating a real boundary grain. The study of solid solutions consisting of four elements will serve as a basis for obtaining complex perovskites, and finally more sophisticated solid solutions. Distribution of angles, coordination number, and distribution function of pairs and the effects of pressure and temperature on the structural and dynamic properties, density of vibrational modes, Debye-Waller factor and the thermal expansion coefficient may be described by the method. This work is part of the thematic project financed by FAPESP, Process No. 2008/04025-0.