Thermally activated energy and critical magnetic fields of SmFeAsO_0.9F_0.1

Abstract

Thermally activated flux flow and vortex glass transition of recently discovered SmFeAsO0.9F0.1 superconductor are studied in magnetic fields up to 9.0 T. The thermally activated energy is analyzed in two analytic methods, of which one is conventional and generally used, while the other is closer to the theoretical description. The thermally activated energy values determined from both methods are discussed and compared. In addition, several critical magnetic fields determined from resistivity measurements are presented and discussed.

Doping dependence of the upper critical field, superconducting current density and thermally activated flux flow activation energy in polycrystalline CeFeAsO 1- x F x superconductors

“…High  values can also occur via plastic deformation of the flux line lattice at dislocations such as those observed in some HTSCs [37]. The range of U0(B) values at 1 Tesla is similar to those found in Ce-based 1111 (U0(1 T) ~ 426-1374 K) [7] and La-based 1111 (U0(1 T) ~ 662-800 K) [7], but is much smaller than that found in Sm-based 1111 (U0(1 T) ~ 5605-12482 K) [38,39] and Ndbased 1111 (U0(1 T) ~ 1794-9804 K) [32] superconductors, indicating a lower pinning force for La-and Ce-based 1111 superconductors.…”

Superconducting and Insulating Phases of Disordered FeSe Thin Films in a Magnetic Field

“…2. Nonetheless, it is a clear indication to TAFF behavior together with many other measurements on Fe-based superconductors interpreted with the TAFF model [10][11][12][13][14]. TAFF fits over restricted resistance, temperature, and magnetic-field ranges with U small compared to T are often reported in the context of a SIT [15,16].…”

Iron chalcogenide superconductors at high magnetic fields

“…On the other hand, the log ρ(T, µ 0 H ) lines for different fields extrapolate to one temperature T cross ∼ 32 K for both field directions, consistent with the values of T c within the error bars. The U 0 (µ 0 H ) values obtained for both superconductors are much larger than in FeCh-11 materials; they are comparable to that in polycrystalline NdFeAsO 0.7 F 0.3 [51], but are still much smaller than in polycrystalline SmFeAsO 0.9 F 0.1 [58]. The power-law fitting yields α = 0.78 (2) …”

“…The nonlinear temperature dependence of U 0 (T, µ 0 H ) and non-constant prefactor ρ 0 f are also common to other iron-based superconductors [58,59]. It should be noted that the low volume fraction of superconductivity in Fe(Te,S) should not significantly affect the analysis of TAFF.…”