Growth, structural characterization, DFT study, and magnetic properties of the NdAuIn crystal

Abstract

A crystal of NdAuIn was successfully grown using the optical floating zone technique. Single-crystal and powder XRD studies confirmed that NdAuIn adopts a hexagonal ZrNiAl-type structure. Comparative analysis of the crystal morphology was performed using the Bravais-Friedel, Donnay-Harker (BFDH) model. DTA analysis revealed that the NdAuIn phase melts congruently at 1136°C. The DFT-calculated enthalpy of formation is −774.192 meV/atom. A thermal expansion coefficient α = 4.1(3) × 10−5 K−1 was derived from the single crystal XRD measurements at 100, 200, and 300 K. The Sommerfeld coefficient γ of 1.262 (mJ/mol × K2) derived from the DFT calculations and the distribution of the density of electronic states, predict metallic conductivity for NdAuIn. The analysis of the charge density difference and Bader charge analysis show that the NdAuIn compound might be treated as polar intermetallic with negatively charged [AuIn]n− and positively charged Ndn+ sublattices. Magnetization measurements with the field parallel and perpendicular to the six-fold axis of the crystal revealed that NdAuIn is a Curie-Weiss paramagnet down to 25 K with an effective magnetic moment of ∼3.62 μB/Nd, which corresponds to the Nd3+ ion. The compound exhibits antiferromagnetic ordering at TN ∼2.4 K.