Noncollinear magnetic order and electronic properties of U2Pd2Sn and U3P4

We report results of calculations that explain in the itinerant electron picture the noncollinear magnetic structure observed in the two very different compounds U2Pd2Sn and U3P4 We use the local approximation to spin-density functional theory and the ASW method incorporating spin-orbit coupling (SOC), noncollinear moment arrangements and an effective orbital field responsible for Hund's second rule. We show how the relativistic effect of SOC and the particular symmetry properties of the compounds cooperate and lead to noncollinear magnetic structures, in the case of U2Pd2Sn to an antiferromagnetic and in the case of U3P4 to a ferromagnetic structure, the latter possessing a weak antiferromagnetic component.