Disclinations are linear defects in ordered media. Perfect disclinations are responsible for the local change of rotational symmetry in conventional and liquid crystals and other physical objects [1]. Partial disclinations in crystalline solids are related to terminated boundaries of crystal lattice misorientation [1]. In elastic continua, disclinations generate long-range elastic fields with typical logarithmic divergence at large distances. To diminish large stored elastic energy, disclinations tend to form so-called screened configurations with opposite sign defects: dipoles, quadrupoles, and loops, or prefer to nucleate in nano- and microobjects where their elastic fields are modified because of a free surface effect. In the present talk we report on the geometrical and energy properties of disclinations in micro- and nanoobjects [3], provide the results on the observation of disclinations in small crystalline particles and nanorods [3], and discuss the role of disclinations in the explanation of a number of physical phenomena for micro- and nanoobjects [3].
[1] A.E. Romanov, A.L. Kolesnikova, Progr. Mater. Sci. 54 (2009) 740.
[2] A.E. Romanov, European J. Mech. A 22 (2003) 741.
[3] V.G. Gryaznov, J. Heydenreich, A.M. Kaprelov, S.A. Nepijko, A.E. Romanov, J. Urban, Cryst. Res. Techn. 34 (1999) 1091.