Break-down of Hund's third rule for induced magnetism in U metal.

An example of a breakdown of Hund's third rule for a system with less than a half filled electronic shell is presented. By means of spin polarized electronic structure calculations including the relativistic effects and a Zeeman term, we demonstrate that in the field induced magnetic state of uranium the spin and orbital moments are coupled parallel rather than antiparallel as stipulated by Hund's third rule. This provides an explanation for the measured field induced magnetic form factor of uranium metal