Thickness-induced crossover from strong to weak collective pinning in exfoliated FeTe0.6Se0.4 thin films at 1 T

We studied flux pinning in exfoliated FeTe0.6Se0.4 thin-film devices with a thickness d from 30 to 150 nm by measuring the critical current density J(c). In bulk FeTe0.6Se0.4, the flux pinning has been discussed in the framework of weak collective pinning, while there is little knowledge on the pinning mechanism in the thin-film region. From the thickness d dependence of J(c) at a fixed magnetic field of 1 T, we found that the strong pinning is dominant below d approximate to 70 nm, while the weak collective pinning becomes more important above d approximate to 100 nm. This crossover thickness can be explained by the theoretical model proposed by van der Beek et al. [Phys. Rev. B 66, 024523 (2002)].

Automated summary

Flux pinning in exfoliated FeTe0.6Se0.4 thin-film devices was studied, where strong pinning is dominant below approximately 70 nm thickness and weak collective pinning becomes more important above approximately 100 nm thickness. This crossover thickness phenomenon can be explained by a theoretical model proposed by van der Beek et al.