English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report B_c2 data for LaO_{0.9}F_{0.1}FeAs_{1-delta} in a wide T and fieldrange up to 60 Tesla. The large slope of B_c2 approx ~ -6 Tesla/K near animproved T_c = 28.5 K of the in-plane B_c2(T) contrasts with a flatteningstarting at 23 K above 30 Tesla we regard as the onset of Pauli-limitedbehavior (PLB) with B_c2(0) about 65 Tesla. We interpret a similar hithertounexplained flattening of the B_c2(T) curves reported for at least three otherdisordered closely related systems as also as a manifestation of PLB. TheirMaki parameters have been estimated analyzing their B_c2(T) data within the WHHapproach. The pronounced PLB of (Ba,K)Fe_2As_2 single crystals from a tin-fluxis attributed also to a significant As deficiency. Consequences of our resultsare discussed in terms of disorder effects within conventional (CSC) andunconventional superconductivity (USC). USC scenarios with nodes on individualFermi surface sheets (FSS), can be discarded for our samples. The increase ofdB_c2/dT|_{T_c} by sizeable disorder provides evidence for an importantintraband (intra-FSS) contribution to the orbital upper critical field. Wesuggest that it can be ascribed either to an impurity driven transition froms_{+-} USC to CSC of an extended s_{++}-wave state or to a stabilizeds_{+-}-state provided As-vacancies cause predominantly strong intrabandscattering in the unitary limit. We compare our results with B_c2 data from theliterature with no PLB for fields below 60 to 70 Tesla probed so far. A noveldisorder related scenario of a complex interplay of SC with two differentcompeting magnetic instabilities is suggested.

Orbital and spin effects for the upper critical field in As deficient disordered Fe pnictide superconductors