Electron Counts, Structural Stability, and Magnetism in BaCuSn$_2$-CeNi$_1$$_-$$_x$Si$_2$-type YT$_x$Ge$_2$ (T= Cr, Mn, Fe, Co, and Ni)
| Autor: | Gustin, Lea, Xing, Lingyi, Pan, Max T., Jin, Rongying, Xie, Weiwei |
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| Rok vydání: | 2017 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Results of crystallographic refinement, the relationship between electron counts and structural stability, and magnetic characterization of YT$_x$Ge$_2$ (T= Cr, Mn, Fe, Co, and Ni) prepared using the arc melting method are presented. These YT$_x$Ge$_2$ compounds crystallize in the BaCuSn$_2$-CeNi$_1$$_-$$_x$Si$_2$-type structure with space group Cmcm, and the site occupancies of 3d transition metals range from x = 0.22(1) for Cr to x = 0.66(1) for Ni. Based on a combination of single crystal and powder X-ray diffraction and scanning electron microscopy, the trends are clearly established that the smaller transition metal atoms exhibit larger occupancies on T (Cu) site. Our investigation into the relationship between electron count and site defect reveals that a stable configuration is obtained when reaching 10.3e- per transition metal (Y+T), which strongly correlates with the defect observed in the case of T metals. Magnetic properties measurements indicate paramagnetism for T = Cr, Fe, and Co, but ferromagnetism for T = Mn with a Curie temperature at 293 K and effective moment ~ 3.6 uB/Mn. The absence of superconductivity in this series is surprising because they consist of similar building blocks and electron counts to superconducting YGe$_1$$_.$$_5$$_+$$_d$Si$_2$ 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. Comment: 17 pages, 4 figures |
| Databáze: | arXiv |
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