We are investigating the design and synthesis of new Pb-free ferroelectrics that also offer long-range magnetic ordering at high temperatures by appropriate compositional tuning, opening a door to new ?multiferroic? materials that could underpin a new generation of data storage devices. We propose to characterise the nuclear and magnetic structures of a new series of magnetic ferroelectrics, [1-x]BiFeyTi(1-y)/2Mg(1-y)/2O3 ? [x]CaTiO3, which will allow us to rationalise and control the key functional properties (switchable polarisation, spontaneous magnetisation and magnetoelectric coupling) offered by this system at room temperature.