Structural and magnetic properties of the Kondo insulator UFe4P12

Neutron-diffraction results on single crystalline UFe4P12 are reported, The structural parameters of UFe4P12 have been determined at 15 K. Below 3.1 K , we find that there is an additional magnetic contribution on top of nucle ar reflections at higher d spacings. An intensity analysis of the magnetic contributions corroborates a ferromagnetic ground state with U moments only . It is argued that this compound forms three magnetic domains with an uppe r limit of about 0.5 mu(B) (at 2.8 K) for the U moment. (C) 1999 Elsevier S cience B.V. All rights reserved.