Crystal, electronic and magnetic structures of a novel series of intergrowth carbometalates R4Co2C3 (R = Y, Gd, Tb)

Volodymyr Levytskyi (1) , Olivier Isnard (2) , Reinhard K. Kremer (3) , Volodymyr Babizhetskyy (4) , Bruno Fontaine (5) , Xavier Rocquefelte (5) , Jean-François Halet (5, 6, 7) , Roman Gumeniuk (1)

1 TU Bergakademie Freiberg - Technishe Universität Bergakademie Freiberg
2 NEEL - MRS - Matériaux, Rayonnements, Structure
3 Max Planck Institute for Solid State Research
4 Ivan Franko National University of Lviv
5 ISCR - Institut des Sciences Chimiques de Rennes
6 NIMS - National Institute for Materials Science
7 LINK - Laboratory for Innovative Key Materials and Structures

A series of new ternary isostructural RCoC (R = Y, Gd, Tb) carbides was synthesized by annealing of arc-melted stoichiometric samples. The crystal structure of TbCoC [space group P2/m, Pearson symbol mP18, a = 12.754(2) Å, b = 3.6251(4) Å, c = 7.0731(9) Å, β = 105.601(6)°] was solved by direct methods from neutron powder diffraction data collected at 100 K. The room temperature unit cell parameters of the new phases were determined by X-ray powder diffraction technique. The crystal structure of TbCoC is characterized as an intergrowth structure resulting from the stacking of alternating TbCoC (YCoC-type) and TbC (anti-CdCl type) fragments with a 2 : 1 ratio. TbCoC orders ferromagnetically at T = 35(1) K, whereas the isostructural GdCoC reveals two magnetic transitions at T = 82(3) K and T = 13(2) K. Density functional theory (DFT) calculations confirm that the magnetic moments of the RCoC (R = Gd, Tb) carbides are exclusively due to the rare-earth elements. YCoC is shown to be a Pauli-paramagnet by experimental and theoretical studies.

Domaines: Matériaux; Cristallographie

Volodymyr Levytskyi, Olivier Isnard, Reinhard K. Kremer, Volodymyr Babizhetskyy, Bruno Fontaine, et al.. Crystal, electronic and magnetic structures of a novel series of intergrowth carbometalates R4Co2C3 (R = Y, Gd, Tb). Dalton Transactions, 2021, 50 (12), pp.4202-4209. ⟨10.1039/d1dt00420d⟩. ⟨hal-03217047⟩