High-pressure x-ray studies of the UCo3B2 compound and ambient magnetic properties

Substituting B for Co in the strong permanent magnet materials ACo 5 (A = Ln or U) substantially modifies the magnetic properties as a function of the B/Co ratio. Preliminary neutron diffraction studies on TbCo 3 B 2 show site-dependent magnetic moments for both the Tb and the Co atoms. The changing interatomic distances and magnetic properties with changing B/Co ratio lead to a rich magnetic phase diagram as a function of pressure. It is our intention to study some of these materials using high-pressure Mossbauer spectroscopy in the future. As a preliminary step it is essential to study the high-pressure crystallographic phase diagram of these materials. This work shows preliminary high-pressure crystallographic results on UCo 3 B 2 to 42 GPa, indicating a phase transition around 6 GPa.