Structural and magnetic properties of RFe4P12 (R=Pr, Nd) studied by neutron diffraction

Abstract In this work we present a neutron powder diffraction study of the ternary rare-earth phosphides PrFe 4 P 12 and NdFe 4 P 12 . High-resolution measurements of the structural temperature dependence reveal large-amplitude thermal vibrations of the rare-earth ions, consistent with speculations that the ion is weakly bound in an oversized atomic ‘cage’ formed in the skutterudite crystal structure. In addition, low temperature neutron diffraction measurements of RFe 4 P 12 (R=Pr, Nd) were performed. Whereas the proposed long-range antiferromagnetic ordering in PrFe 4 P 12 could not be confirmed, NdFe 4 P 12 orders ferromagnetically below T C =1.94 K with an ordered magnetic Nd 3+ moment of 1.61(7) μ B at 1.5 K.