Single crystals of ${\mathrm{Nd}}_2{\mathrm{O}}_3$ were grown and characterized using neutron scattering and thermodynamic measurements. ${\mathrm{Nd}}_2{\mathrm{O}}_3$ has long-range antiferromagnetic order below $T_{\mathrm{N}}=0.55$ K and specific-heat measurements have demonstrated that a significant amount of the magnetic entropy is released above $T_{\mathrm{N}}$. Inelastic neutron scattering experiments reveal a magnetic mode(s) with little dispersion peaked at $\approx 0.37\mathrm{meV}$ that is of greatest intensity below $T_{\mathrm{N}}$ but persists above $2T_{\mathrm{N}}$. This persistence of dynamic correlations is likely related to frustrated interactions associated with the nearly ideal stacked triangular lattice geometry of $J_{\text{eff}}=\frac{1}{2}$ spins on ${\mathrm{Nd}}^{3+}$ ions. The magnetization is observed to be strongly anisotropic at all temperatures due to crystal field effects, with easy-plane anisotropy observed. A noncompensated magnetic structure is inferred from the temperature dependence of the magnetization when a magnetic field of sufficient strength is applied within the basal plane near $T_{\mathrm{N}}$, and the evolution of the long-range order is summarized in a temperature-field phase diagram.

• Received 21 May 2020
• Revised 27 July 2020
• Accepted 5 August 2020

DOI:https://doi.org/10.1103/PhysRevB.102.054434