Superconductivity in the η-carbide-type oxides Zr4 Rh2 Ox

• Published in: Journal of alloys and compounds Vol. 796; p. 287
• Main Authors: Ma, KeYuan, Lago, Jorge, von Rohr, Fabian O
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier BV 05.08.2019
• Subjects: Carbides; Physical properties; Superconductivity
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.04.318

We report on the synthesis and the superconductivity in Zr4 Rh2 Ox (x = 0.4, 0.5, 0.6, 0.7, 1.0). These compounds crystallize in the η-carbide structure, which is a filled version of the complex intermetallic Ti2Ni structure. We find that in the system Zr4 Rh2 Ox, already a small amount (x ≥ 0.4) of oxygen addition stabilizes the η-carbide structure over the more common intermetallic CuAl2 structure-type, in which Zr2 Rh crystallizes. We show that Zr4 Rh2 O0.7 and Zr4 Rh2 O are bulk superconductors with critical temperatures of Tc ≈ 2.8 K and 4.7 K in the resistivity, respectively. Our analysis of the superconducting properties reveal both compounds to be strongly type-II superconductors with critical fields up to μ0 Hc1 (0) ≈ 8.8mT and μ0 Hc2 (0) ≈ 6.08T. Our results support that the η-carbides are a versatile family of compounds for the investigation of the interplay of interstitial doping on physical properties, especially for superconductivity.