Magnetic structure and supermagnetic properties of δ-FeOOH

A synthetic polycrystalline sample of hexagonal δ-FeOOH was studied by neutron diffraction and Mössbauer effect measurements at various temperature. Below 450 K, the crystallomagnetic structure consists in an antiferromagnetic coupling of ferric ions which occupy two octahedral sites. The magnetic moments lying along the c-axis are parallel within a given