Not everything is ferromagnetic in high magnetic fields

The physicists examined crystals of U2Pd2In, which form a special class of solids (Shastry-Sutherland system). The interactions between the magnetically active uranium atoms are quite complex in this structure, mainly due to the extended 5f orbitals of the outermost electrons of uranium in a solid. These 5f electrons are also carriers of the magnetic moment in the material.

Using neutron diffraction in strong fields they found that an unusually complicated non-collinear modulated magnetic structure above a critical magnetic field. The magnetic unit cell is twenty times larger than the crystallographic unit, containing 80 magnetic moments. Such a structure is a consequence of competition between different strong interactions and the applied field. "Our results are important from two reasons," Dr. Karel Prokes (HZB) says. "First, they show that the field induced phase is not ferromagnetic and the magnetization increase at high fields is probably due to a gradual rotation of U moments towards the field direction, a finding that might be of relevance for many other systems and second, they may help to develop more precise theories dealing with 5f electron systems."