Structural and magnetic properties of the interstitial carbide-hydride NdScSiC0.5H0.2

JOURNAL OF ALLOYS AND COMPOUNDS

卷:844

Article

Mahon, Tadhg¹  Gaudin, Etienne¹  Nassif, Vivian²  Tence, Sophie¹ 

[1] Univ Bordeaux, CNRS, Bordeaux INP, ICMCB,UMR 5026, F-33600 Pessac, France

[2] Inst Laue Langevin, 71 Ave Martyrs,CS 20156, F-38042 Grenoble 9, France

关键词: Carbide-hydride;    Intermetallic;    Neutron diffraction;    Magnetic structure;   

DOI  :  10.1016/j.jallcom.2020.156105

来源: Elsevier

【 摘 要 】

We report the synthesis of the first carbide-hydride phase obtained in the family of equiatomic intermetallics RTX (R = rare earth, T = transition metal, X =p-block element) by insertion of light elements. We prepared the NdScSiC0.5H0.2 compound by solid-gas reaction, by exposing the carbide NdScSiC0.5 to 40 bars of H-2 gas at 450 degrees C. It crystallizes in the La2Fe2Se2O3-type structure with H and C atoms occupying Nd-4 tetrahedral and Nd2Sc4 octahedral interstices, respectively. The H site is only partly filled owing to the presence of Nd-C covalent bonding that prevents the formation of Nd-H bonding through antagonist effect. The carbide-hydride was characterized through magnetic measurements, specific heat and powder neutron diffraction. Remarkably, hydrogenation of the carbide provokes a quite drastic effect on the magnetic properties by changing the ground state from a ferromagnetic (T-C similar to 70 K) to an antiferromagnetic one (T-N = 10 K). The magnetic structure of NdScSiC0.5H0.2 consists of double layers of ferromagnetic Nd moments aligned along the c-axis and coupled antiferromagnetically along this axis. This magnetic structure results in a field-induced metamagnetic behaviour as pointed out by magnetisation isotherms. (C) 2020 Elsevier B.V. All rights reserved.

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