Electron counts, structural stability, and magnetism in BaCuSn2-CeNi1-xSi2-type YTxGe2 (T = Cr, Mn, Fe, Co, and Ni)

JOURNAL OF ALLOYS AND COMPOUNDS

卷:741

Article

Gustin, Lea¹  Xing, Lingyi²  Pan, Max T.¹  Jin, Rongying²  Xie, Weiwei¹ 

[1] Louisiana State Univ, Dept Chem, Baton Rouge, LA 70803 USA

[2] Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA

关键词: BaCuSn2-type;    CeNi1-xSi2-type;    Layered intermetallics;    Superconductivity;    Ferromagnetism;   

DOI  :  10.1016/j.jallcom.2018.01.093

来源: Elsevier

【 摘 要 】

Results of crystallographic refinement, the relationship between electron counts and structural stability, and magnetic characterization of YTxGe2 (T = Cr, Mn, Fe, Co, and Ni) prepared using the arc melting method are presented. These YTxGe2 compounds crystallize in the BaCuSn2-CeNi1-xSi2-type structure with space group Cmcm, and the site occupancies of 3d transition metals range from x = 0.22 (1) for Cr to x = 0.66 (1) for Ni. Based on a combination of single crystal and powder X-ray diffraction and scanning electron microscopy, the trends are clearly established that the smaller transition metal atoms exhibit larger occupancies on T (Cu) site. Our investigation into the relationship between electron count and site defect reveals that a stable configuration is obtained when reaching 10.3e- per transition metal (Y + T), which strongly correlates with the defect observed in the case of T metals. Magnetic properties measurements indicate paramagnetism for T = Cr, Fe, and Co, but ferromagnetism for T = Mn with a Curie temperature of similar to 293 K and effective moment similar to 3.6 mu B/Mn. The absence of superconductivity in this series is surprising because they consist of similar building blocks and electron counts to superconducting YGe1.5+delta except for 3d transition metals. Introducing 3d transition metals into the system plays a critical role in suppressing superconductivity, offering new insights into the interplay between superconductivity and magnetism in layered intermetallics. (C) 2018 Elsevier B.V. All rights reserved.

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