We propose to study polarised neutron reflectivity from a GdCo/Si/Co/Si multilayers. Magnetic rare earth/transition metal (RE/TM) multilayers have been subject of considerable interest in recent years due to their interesting magnetic properties, with aligned and twisted magnetic state of the multilayers at low fields and high fields respectively. In our case the RE element have been replaced by a RE-TM alloy, with Curie point far above room temperature, being better for applications, and we have also introduced a non magnetic spacer which affects the magnetic coupling between layers. We want to study, using polarised neutron reflectometry with an analyser, how the spacer affect the twisted state appearing at high field using exactly the same multilayer measured in our previous experiment in July 2008.