Investigation of a great number of physical systems shows that a scaled Landau free energy density of the form F(φ) = a/2φ2 - 1/4φ4 + 1/6φ6 describes a first-order phase transition. To study the formation of static domain walls in these systems we include a spatial gradient (Ginzburg) term of the scalar order parameter φ. At the transition temperature (Tc) the potential has three degenerate minima corresponding to an asymmetric domain wall (i.e. a half-kink solution). We have obtained the associated kink lattice solution, its energy of formation and asymptotic kink-kink interaction. In addition, we report a 'pulse' lattice solution below Tc.