Influence of cubic anisotropy in dipole-dipole interactions on structural phase transitions using the renormalization group transformation

The critical behaviour of ferroelectrics is studied forT>T _c and for zero electric field, by the renormalization group techniques ind=3 dimensions. The model hamiltonian we used contains an isotropic exchange coupling and a dipolar interaction with strong cubic anisotropy. A quadratic anisotropic fixed point is found to be stable for the cubic anisotropic scale field. Experiments on BaTiO₃ and KTaO₃ are compared with our results.Work supported by N.F.W.O.