Superconductivity in monocrystalline YNiSi 3 and LuNiSi 3

作者：Fabiana R. Arantes, Deisy Aristizábal-Giraldo, D. A. Mayoh, Yu Yamane, Chongli Yang, M. R. Lees, J. M. Osorio-Guillén, T. Takabatake, M. A. Ávila · 发表于：Physical review. B./Physical review. B · 年份：2019 · DOI：10.1103/physrevb.99.224505 · 被引用次数：10 · 研究领域：Rare-earth and actinide compounds、Iron-based superconductors research、Magnetic and transport properties of perovskites and related materials

We report the discovery of bulk superconductivity in the ternary intermetallics ${\mathrm{YNiSi}}_{3}$ and ${\mathrm{LuNiSi}}_{3}$. High-quality single crystals were grown via the Sn-flux method and studied using magnetization, specific-heat, and resistivity measurements at low temperatures. The critical temperatures obtained from these different techniques are in very good agreement and yield ${T}_{\mathrm{c}}=1.36(3)\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ and ${T}_{\mathrm{c}}=1.61(2)\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ for ${\mathrm{YNiSi}}_{3}$ and ${\mathrm{LuNiSi}}_{3}$, respectively. Magnetization measurements indicate that both compounds are among the rare cases where type-I superconductivity occurs in a ternary intermetallic, however, the jump in the specific heat at the transition is lower than the value expected from BCS theory ($\mathrm{\ensuremath{\Delta}}{C}_{\mathrm{el}}/{\ensuremath{\gamma}}_{\mathrm{n}}{T}_{\mathrm{c}}=1.43$) in both materials and is equal to 1.14(9) and 0.71(5) for the Y and Lu compounds, respectively. Resistivity measurements exhibit sharp transitions but with critical fields ${\ensuremath{\mu}}_{0}{H}_{\mathrm{c}}(0)$ ($\ensuremath{\approx}0.05\phantom{\rule{0.28em}{0ex}}\mathrm{T}$ for ${\mathrm{YNiSi}}_{3}$ and $\ensuremath{\approx}0.08\phantom{\rule{0.28em}{0ex}}\mathrm{T}$ for ${\mathrm{LuNiSi}}_{3}$) considerably higher than those obtained from the magnetization and specific heat ($\ensuremath{\approx}0.01\phantom{\rule{0.28em}{0ex...