Polichetti M, Galluzzi A, Buchkov K, Tomov V, Nazarova E, Leo A, Grimaldi G, Pace S
Department of Physics "E.R. Caianiello", University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, Salerno, Italy.
CNR-SPIN Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, Salerno, Italy.
Sci Rep. 2021 Mar 31;11(1):7247. doi: 10.1038/s41598-021-86728-8.
The correlation in type-II superconductors between the creep rate S and the Second Magnetization Peak (SMP) phenomenon which produces an increase in J, as a function of the field (H), has been investigated at different temperatures by starting from the minimum in S(H) and the onset of the SMP phenomenon detected on a FeSeTe sample. Then the analysis has been extended by considering the entire S(H) curves and comparing our results with those of many other superconducting materials reported in literature. In this way, we find evidence that the flux dynamic mechanisms behind the appearance of the SMP phenomenon in J(H) are activated at fields well below those where the critical current starts effectively to increase. Moreover, the found universal relation between the minimum in the S(H) and the SMP phenomenon in J(H) shows that both can be attributed to a sequential crossover between a less effective pinning (losing its effectiveness at low fields) to a more effective pinning (still acting at high fields), regardless of the type-II superconductor taken into consideration.
通过从FeSeTe样品上检测到的S(H)最小值和第二磁化峰（SMP）现象的起始点出发，在不同温度下研究了II型超导体中蠕变速率S与产生J增加的第二磁化峰（SMP）现象之间的相关性，该相关性是场强（H）的函数。然后，通过考虑整个S(H)曲线并将我们的结果与文献中报道的许多其他超导材料的结果进行比较，扩展了分析。通过这种方式，我们发现有证据表明，J(H)中SMP现象出现背后的磁通动力学机制在远低于临界电流开始有效增加的场强下被激活。此外，在S(H)最小值与J(H)中的SMP现象之间发现的普遍关系表明，两者都可归因于从效率较低的钉扎（在低场强下失去其有效性）到效率更高的钉扎（在高场强下仍起作用）的顺序转变，而与所考虑的II型超导体类型无关。
