Physical Properties Of The Trigonal Binary Compound Nd2o3

We have studied the physical properties of Nd2O3 with neutron diffraction, inelastic neutron scattering, heat-capacity, and magnetic susceptibility measurements. Nd2O3 crystallizes in a trigonal structure with Nd3+ ions surrounded by cages of seven oxygen anions. The crystal-field spectrum consists of four excitations spanning the energy range of 3-60 meV. The refined eigenfunctions indicate XY spins in the ab plane. The Curie-Weiss temperature of theta(cw) = -23.7(1) K was determined from magnetic susceptibility measurements. Heat capacity measurements show a sharp peak at 550 mK and a broader feature centered near 1.5 K. Neutron diffraction measurements show that the 550 mK transition corresponds to long-range antiferromagnetic order implying a frustration index of theta(cw) / T-N approximate to 43. These results indicate that Nd2O3 is a structurally and chemically simple model system for frustration caused by competing interactions with moments with predominant XY anisotropy.