AI 中文总结
研究 NiBi3 单晶的物理及超导特性，通过多种测量和数据分析，包括估算上临界场、确定相干长度等，发现其为典型的 II 型、类 BCS、中等强耦合且完全能隙超导体，揭示了其超导态的相关特性。
AI 中文摘要
我们研究了 NiBi3 单晶的物理特性、正常态和超导特性。电阻率、磁化强度和伦敦穿透深度测量表明超导转变温度 Tc = 4.0 K，电阻率转变 sharp（Tc = 0.20 K）且 RRR = 18，反映单晶质量高。通过 NiBi3 单晶 H 垂直 b 和 H 平行 b 两种取向的磁化数据估算上临界场 Hc2，两种取向 Hc2 均显著小于泡利极限，表明超导态存在轨道对破坏。相干长度 xi(0) = 26.78 nm、电子 - 声子耦合常数 lambda(e - p) = 0.81、穿透深度 lambda0 = 181.8 nm，表明 NiBi3 为 II 型超导。超导态下 lambda(T) 最好用 s 波 BCS 模型描述，与无节点超导序参量预期相符。超流密度温度演化揭示 NiBi3 存在完全能隙超导，超导能隙 = 4.07。本研究所有结果表明 NiBi3 是脏极限下典型的 II 型、类 BCS、中等强耦合且完全能隙超导体。
英文摘要
We investigate the physical characteristics, normal state and superconducting properties of NiBi3 single crystals. Measurements of electrical resistivity, magnetization, and London penetration depth demonstrate a superconducting transition temperature, Tc=4.0 K, with a sharp transition in resistivity (Tc = 0.20 K) and RRR = 18, reflecting the high quality of NiBi3 single crystals. With both orientations H perpendicular b and H parallel b of NiBi3 single crystals, we estimated the upper critical field, Hc2, from the magnetization data. In both orientations, Hc2 is significantly smaller than the Pauli limit, suggesting the orbital pair breaking in superconducting state. The coherence length, xi(0) = 26.78 nm, electron-phonon coupling constant, lambda(e-p) = 0.81, and penetration depth, lambda0 = 181.8 nm, suggest type-II superconductivity in NiBi3. In the superconducting state, lambda(T) is best described by an s-wave BCS model and does not have linear or quadratic dependency with T, which is in line with the expectation for a node-less superconducting order parameter. The temperature evolution of the superfluid density, obtained from lambda(T), reveals a fully gapped superconductivity in NiBi3, with a superconducting gap = 4.07. All the results from the present study indicate that NiBi3 is a typical type-II, BCS-like, moderately strong coupled, and fully gapped superconductor in the dirty limit.
Comments8 pages, 5 figures
