DFT+U search for the energy minimum among eight collinear and noncollinear magnetic structures of GdB_4

摘要

We have studied eight collinear and noncollinear magnetic orientations of GdB_4 using the GGA+ U method, without and with spin-orbit coupling, for values of U-J between 0 and 6. For U - J=6, the value which had been found to yield the correct Gd lattice constants, we obtain GdB_4 lattice constants within 0.26% of experiment. We find that the magnetization lies in plane but is collinear, in disagreement with the most recent experimental determination.