[en] Fine powder samples of substituted Barium M-type haxaferrites with composition BaFe_12-2xCo_xTi_xO₁₉ (0.72< x<0.84) have been studied by macroscopic magnetic measurements (Curie temperature, magnetization, anisotropy field, coercive field) and Moessbauer spectroscopy. The analysis of the magnetization data and of the distribution of Co-Ti among the iron sublattices suggest that the Gorter spin arrangement is no longer valid. The Moessbauer data allow to rule out the possible presence of superparamagnetic fine particles as the origin of the observed scattering in the magnetization values. (orig.)