Magnetic Compton scattering study of NpNiGa5

We have carried out the magnetic Compton scattering of NpNiGa5. The signs of the magnetic effects in both ordered states are negative. These facts demonstrate that the contribution of the Np 5f electrons is dominant in the ordered states of NpNiGa5. The magnetic Compton profile shows significant change across the successive transitions. This suggests that the successive transitions are correlated with the 5f quadrupolar degrees of freedom and/or the change of the quantized axis.