FIELD-INDUCED MAGNETISM IN ITINERANT F-ELECTRON SYSTEMS - U, PU, AND CE

We demonstrate, by means of first-principles calculations, that in the field-induced magnetic state of alpha-cerium and alpha-uranium the spin and orbital moments are coupled parallel rather than antiparallel as expected from Hund's third rule. This behavior gives a magnetic form factor for alpha-uranium in very good agreement with experiment. The calculated form factor of alpha-cerium, when assuming that the f electron is itinerant, is very different from the localized Ce3+ form factor, and we propose that a measurement of the magnetic form factor of alpha-Ce can indicate whether the f state is localized or itinerant. The held-induced magnetism of plutonium is shown to be almost exclusively of orbital character and the induced spin density of plutonium is highly anomalous.