A revised Hamiltonian of a one-dimensional (ID) easy-plane ferromagnet in which the dipole–dipole and biquadratic exchange interactions are taken into account in addition to the Zeeman energy, the uniaxial anisotropy and the exchange energy, is proposed. Using a classical approximation, in the continuum limit, we show that in certain ranges of coupling constants, domain-walls in such a ferromagnet can be approximated by the perturbed sine Gordon (s.G) equation. In the case of weakly dipolar coupling, an analysis of the general properties of the soliton's motion as well as its modified profile are examined within the context of the perturbation theory. From a Ginzburg-Landau expansion of the free energy, it comes that one of the dipolar effects is to increase the stability of the sG solitons. The soliton contribution to the specific heat at low temperatures is obtained. We also investigated the transport properties in materials such as CsNiF3.