ScAuIn – A new representative of the RAuIn series

V.V. Romaka, L. Amigo, D. Franco, L.T. Corredor, S. Wurmehl, B. Büchner, S. Seiro J. Solid State Chem. 314, 123416 (2022)

A new representative of the RAuIn series was discovered in the Sc-Au-In system. ScAuIn crystallizes in the hexagonal HfRhSn-type structure (space group P-62c) with a ​= ​0.75667(2), c ​= ​0.71873(2) nm). Magnetization measurements revealed that ScAuIn is a Pauli paramagnet with magnetic susceptibility of ∼6 ​× ​10−5 emu/mol. The Sommerfeld coefficient γ of 2.8 ​mJ ​K−2 ​mol−1 derived from the specific heat measurements is comparable with those obtained from the modeled density of states at the Fermi level N(EF). Ab initio calculations predict metallic conductivity and show strong chemical bonding within the [InAu] sublattice. The structural stability of the RAuIn with ZrNiAl and HfRhSn structure types is discussed based on crystal chemistry analysis and DFT modeling.

FeMn3Ge2Sn7O16: A Perfectly Isotropic 2-D Kagomé Lattice that Breaks Magnetic Symmetry with Partial Spin Order

M. C. Allison, S. Wurmehl, B. Büchner, J.  L. Vella, T. Söhnel, S. A. Bräuninger, H.-H. Klauss, M. Avdeev, F. P. Marlton, S. Schmid, C. D. Ling

Chem. Mater. 34, 1369 (2022)

FeMn3Ge2Sn7O16 is a fully ordered stoichiometric phase containing an undistorted hexagonal kagomé lattice of Mn2+ cations. It represents not only an important expansion of the chemistry of the complex composite FeFe3Si2Sn7O16 structure type, by replacing silicon with germanium, but also an improvement on the perfection of the kagomé lattice by replacing anisotropic high-spin Fe2+ (d6, L = 2) with isotropic high-spin Mn2+ (d5, L = 0), controlled by the size-matched replacement of SiO44– with GeO44– bridging units. This anisotropy was suspected of playing a role in the unique “striped” magnetic structure of FeFe3Si2Sn7O16 at low temperatures, which breaks hexagonal symmetry and leaves one-third of the magnetic moments geometrically frustrated and fluctuating down to at least 0.1 K. We observe the same striped magnetic structure in FeMn3Ge2Sn7O16, ruling out single-ion anisotropy as the driving force and deepening the intrigue around the apparent “partial spin-liquid” nature of these compounds.

Evolution of Structure and Electronic Correlations in a Series of BaT2As2 (T = Cr–Cu) Single Crystals

S. Selter, et al., Inorg. Chem. 59, 16913 (2020)

We present a systematic study of the evolution of structural parameters and electronic correlations as a function of 3d band filling in a single crystal series of BaT2As2 (T = Cr–Cu). Our study finds a strong interplay between crystal structure, bonding behavior, band filling, and electronic properties.

Flux growth of Srn+1IrnO3n+1 (n=1, 2, infinity) crystals

K. Manna, et al., J. Cryst. Growth 540, 125657 (2020)

Single crystals of iridates are usually grown by a flux method well above the boiling point of the SrCl2 solvent, hence, under non-equilibrium growth conditions. Here, we report the growth of Sr2IrO4, Sr3Ir2O7 and SrIrO3 single crystals in a reproducible way by using anhydrous SrCl2 flux well below its boiling point. Reducing the soak temperature below the solvent boiling point not only provides more stable and controllable growth conditions in contrast to previously reported growth protocols, but also extends considerably the lifetime of expensive platinum crucibles and reduces the corrosion of heating and thermoelements of standard furnaces, thereby reducing growth costs.