Similar and Dissimilar Properties of Polymorphic Phases of NdIr3

Abstract

We report the formation and physical properties of a new polymorphic phase of NdIr3 (AuBe5-type cubic), along with those of one earlier reported phase (AuCu3-type cubic), formed together during the synthesis process. Our experimental data shows that the magnetic properties of these two phases are of contrasting characters: the former becomes ferromagnetic at low temperatures, while the latter remains paramagnetic down to the lowest measured temperature, 2.5 K. Interestingly, the magnetic properties of the cubic AuBe5-type phase have an uncanny similarity to that recently reported in another polymorphic phase (rhombohedral PuNi3-type) of the same compound. We have investigated the origin of such similarities and dissimilarities in magnetic properties of these three polymorphic phases of NdIr3 through a few diverse directions: structural, theoretically calculated spin-polarized density of states, and magnetic ground state and RKKY framework. We have shown that the similarity of the Curie temperature of the cubic AuBe5-type and rhombohedral PuNi3-type phases is the result of aperiodicity in the first nearest neighbors and similarity in the Fermi momentum space.