Magnetisation densities and uranium form factors in UNiGA and UNiAl

We have studied magnetic form factors and magnetisation density distributio n in UNiGa and UNiAl intermetallics compounds by polarised neutron diffract ion and theoretical ab-initio calculations. Two methods of the analysis of the experimental data were used. One is based on a model-free reconstructio n using the maximum entropy method (MAXENT) and the second fits the model t o experimental data. Both methods are in good agreement giving the followin g results. The main contribution to the total magnetisation has been found located onto uranium atoms. However, small magnetisation clouds have been f ound on the positions of Ni atoms. The experimental results have been confi rmed by ab-initio calculations. The small magnetisation clouds out of the a tomic positions, previously assumed to come from small amount of the inters titial atoms, have been theoretically calculated for a perfect crystal.