Thickness-induced crossover from strong to weak collective pinning in exfoliated FeTe${}_{0.6}$Se${}_{0.4}$ thin films at 1 T

Abstract

We studied flux pinning in exfoliated FeTe${}_{0.6}$Se${}_{0.4}$ thin-film devices with a thickness $d$ from 30 to 150 nm by measuring the critical current density $J_{\mathrm{c}}$. In bulk FeTe${}_{0.6}$Se${}_{0.4}$, 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 $J_{\mathrm{c}}$ at a fixed magnetic field of 1 T, we found that the strong pinning is dominant below $d\approx 70$ nm, while the weak collective pinning becomes more important above $d\approx 100$ nm. This crossover thickness can be explained by the theoretical model proposed by van der Beek $\text{et al}$ [Phys. Rev. B. $66$, 024523 (2002)].

8 pages, 6 figures

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Cited by in corpus (1)

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