We have investigated Np-Ga binary phase diagram by the Ga-flux method. We found a new structure type of NpGa3 with the trigonal R3̄m, instead of the previously reported cubic AuCu3-type NpGa3. This compound orders ferromagnetically at 71 K with a saturation moment 1.55 μB/Np with a strong uniaxial anisotropy along the  direction. From the structural point of view, the AuCu3-type atomic arrangements are well maintained in the R3̄m structure where the trigonal  corresponds to the cubic  direction. The uniaxial magnetic anisotropy in trigonal-NpGa3 is consistent with that of cubic NpGa3 along , suggesting that the magnetic anisotropy is governed by the local crystal field effects. We also found a new compound Np3Ga 11 and its crystal structure is reported.
ASJC Scopus subject areas
- Physics and Astronomy(all)