BiFeO3 is a room temperature multiferroic, displaying both ferroelectric and antiferromagnetic (AFE) ordering. x-BiFeO3 - (1-x)-PbTiO3 is also multiferroic at room temperature for a range of compositions, and has signficant advantages over the BiFeO3 end-member, arising from (1) ease of formation as a single phase material (2) high electrical resistivity and most importantly (3) the possibility of forming two phase perovskite structures (coexistence of tetragonal and rhombohedral phase). We have recently shown that we can switch easily between these structures and turn magnetic ordering on and off, resulting a difference in Neel temperatures. Also, at 4 K, we have confirmed G-type AFE ordering for 0.4<x<1.0. In this experiment we intend to probe the spiral ordering in this class of material for 0.4<x<0.9 on passage from rhombohedral to tetragonal phase, and expect collapse of the spiral