Calculated de Haas-van Alphen frequencies of NpCoGa ₅

The electronic structure and magnetic properties of NpCoGa 5 are investigated in the framework of relativistic density functional theory in the local spin density approximation (LSDA) with and without orbital polarization (OP) corrections. A detailed analysis of the Fermi surface is presented. Comparison of the calculated angular dependence of the de Haas-van Alphen frequencies with recent experimental data shows that LSDA reproduces the main features of the Fermi surface topology, while the spin and orbital moments of NpCoGa 5 are less well described. The inclusion of OP corrections leads to a very good agreement between calculated and measured de Haas-van Alphen frequencies, but does not yield a significant improvement of the calculated magnetic properties. We predict that NpCoGa 5 shows an intrinsic GMR effect at moderate magnetic field.