Rwenyagila, E. R.Mwanga, S. F.2020-03-252020-03-252006Rwenyagila, E. R., & Mwanga, S. F. (2006). Landau theoretical interpretation of domain and domain walls in ferroelectric ferroics. ARPN Journal of Engineering and Applied Sciences, 13 (1), 160-174.http://www.arpnjournals.org/jeas/research_papers/rp_2018/jeas_0118_6649.pdfhttp://hdl.handle.net/20.500.12661/2369Full Text Article. Also available at: http://www.arpnjournals.org/jeas/research_papers/rp_2018/jeas_0118_6649.pdfIn this paper some behaviors of domain and domain walls in perovskite ferroics were theoretically investigated. Landau type theory was used to examine the phenomenological properties of domains and domain walls in ferroelectric perovskite materials. Landau predictions on the prototype ferroelectric BaTiO3 showed that it has a stable tetragonal structure at room temperature. The number of domains in the three ferroelectric phases of BaTiO3 was also calculated. The results confirmed six, eight and twelve domain states in the tetragonal, rhombohedral and orthorhombic structures of BaTiO3, respectively. The respective spontaneous polarization and domain wall thickness in the stable tetragonal BaTiO3 have values of 0.26 Cm-2 and 1.63nm at room temperature. Analytical and numerical solutions for the relationship between temperature and domain wall thickness and for the spatial distribution of polarizations inside the domain wall are also determined and discussed.enDomain wallsLandauFerroelectricityLandau theorySymmetryPerovskite ferroicsArticle