2021/05/31 by Eli Zoghlin, Julian Schmehr, Collin Holgate +4 · 10 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Crystallite #Lattice (music) #Lattice constant #Luminescence Properties of Advanced Materials #Magnetic moment #Neutron #Neutron scattering #Nuclear materials and radiation effects #Scattering #Stoichiometry #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevmaterials.5.084403
published in Physical Review Materials 5(8) (American Physical Society) · 12 pages, 10 figures
openalex created_date 2021/05/24 · openalex publication_date 2021/08/09 · arxiv created 2021/08/16 · arxiv updated 2021/08/18 · openalex updated_date 2026/08/06
Motivated by the variation in reported lattice parameters of floating-zone-grown Nd2Zr2O7 crystals, we have performed a detailed study of the relationship between synthesis environment, structural disorder, and magnetic properties. Using a combination of polycrystalline standards, electron-probe microanalysis, and scattering techniques, we show that crystals grown under atmospheric conditions have a reduced lattice parameter relative to pristine polycrystalline powders due to occupation of the Nd site by excess Zr (i.e., negative stuffing). In contrast, crystals grown under high-pressure Ar are nearly stoichiometric with an average lattice parameter approaching the polycrystalline value. While minimal disorder of the oxygen sublattices is observed on the scale of the average structure, neutron pair-distribution function analysis indicates a highly local disorder of the oxygen coordination, which is only weakly dependent on growth environment. Most importantly, our magnetization, heat capacity, and single-crystal neutron scattering data show that the magnetic properties of crystals grown under high-pressure Ar match closely with those of stoichiometric powders. Neutron scattering measurements reveal that the signature of magnetic moment fragmentation---the coexistence of all-in-all-out (AIAO) magnetic Bragg peaks and diffuse pinch-point scattering due to spin-ice correlations--persists in these nearly stoichiometric crystals. However, in addition to an increased AIAO transition temperature, the diffuse signal is seemingly stabilized and remains nearly unchanged upon warming to 800 mK. This behavior indicates that both the AIAO magnetic order and spin-ice correlations are sensitive to deviations of the Nd stoichiometry.