The perovskite BiFeO3 has received considerable attention over the years due to its unique ferroelectric and multiferroic properties at room temperature. It has been reported that linear magnetoelectric coupling in BiFeO3 can be realized by artificially introduced disorder like in solid solutions. Pure BiFeO3 is characterized by an extremely complicated type of magnetic ordering, which cannot be deduced from conventional neutron powder. In order to deduce the evolution of magnetic and structural ordering as well as their coupling it is proposed to perform high resolution TOF powder diffraction experiment at HRPD on the sequence of solid solutions from the system (1-x)BiFeO3-xPbTiO3.