Speaker
Description
The Co–Zr binary system contains several superconducting intermetallic compounds, including CoZr₂ and CoZr₃, which exhibit critical temperatures ($T_c$) of approximately 5.2 K and 3.4 K, respectively [1, 2]. In this study, we investigate superconducting properties of polycrystalline CoZr₂-based compounds synthesized by self-propagating high-temperature synthesis (SHS) [3], which has rarely been applied to the synthesis of intermetallic superconductors. Although SHS synthesis targeting nominal composition CoZr₂ results in multiphase formation containing CoZr₃ and unidentified phases, a superconducting transition temperature of ~7 K is observed, exceeding the reported $T_c$ of single-phase CoZr₂. In order to investigate the relationship between structural characteristics and superconducting properties, we synthesized samples with systematically varied starting composition in a narrow range around the stoichiometric ratio (Co:Zr ≈ 1:2), specifically from 1:2.10 to 1:1.90. X-ray diffraction confirms the coexistence of multiple phases, including CoZr₂ and CoZr₃, while magnetization and electrical resistivity measurements reveal superconducting transitions primarily originating from the CoZr₂ phase. These results provide insight into the relationship between multiphase formation and superconductivity in Co–Zr intermetallic compounds synthesized by SHS.
References
1. S. L. McCarthy, J. Low Temp. Phys. 4, 489–501 (1971).
2. R. Kuentzler, A. Amamou, R. Clad and P. Turek, J. Phys. F: Met. Phys. 17, 459 (1987).
3. J. Subrahmanyam and M. Vijayakumar, J. Mater. Sci. 27, 6249–6273 (1992).
