We have shown using previous experiments that moderate hydrostatic pressures can be used to switch phase from tetragonal to rhombohedral in the material BiFeO3 - PbTiO3 at room temperature. Allied to this transformation is a modification from para - antiferromagnetic ordering, at moderate pressures of around 700 MPa. This new proposal aims to extend the compositional range previously studied in order to further reduce the switching pressure even further.