Phase diagram of mixed system of ferroelectric relaxors in the random   field theory framework
  We suggest a random field based model for calculation of physical properties of mixed ferroelectric relaxors. Our model naturally incorporates the different orientations of electric dipoles (related to different solid solution components) as well as the contribution of nonlinear and correlation effects of random field. We calculate the transition temperature $T_c$ as well as concentrational and temperature dependence of order parameters. 
M.D.Glinchuk and E.A.Eliseev (Institute for Problems of Materials   Science, Kiev, Ukraine), V.A.Stephanovich (Institute of ...