Ferromagnetism and spin-orbital compensation in Sm intermetallics

The electronic structure and magnetic properties of the ferromagnetic Sm intermetallics SmAl2 and SmZn have been calculated within the local density approximation (LDA)+U method. In contrast to LDA, which predicts a strong peak of 4f character in the density of states on the Fermi level, the LDA+U method predicts occupied 4f states well below the Fermi energy and empty ones well above this energy. We find a sizeable orbital magnetic moment, comparable in magnitude with the opposite oriented spin moment. This result is consistent with the recent observation of ferromagnetic spin ordering, compensated by the orbital magnetization.