Hall coefficient and Hc2 in underdoped LaFeAsO0.95F0.05

Abstract

The electrical resistivity and Hall coefficient of LaFeAsO0.95F0.05 polycrystalline samples were measured in pulsed magnetic fields up to m0H = 60 T from room temperature to 1.5 K. The resistance of the normal state shows a negative temperature coefficient (dr/dT < 0) below 70 K for this composition, indicating insulating ground state in underdoped LaFeAsO system in contrast to heavily doped compound. The charge carrier density obtained from Hall effect can be described as constant plus a thermally activated term with an energy gap DE = 630 K. Upper critical field, Hc2, estimated from resistivity measurements, exceeds 75 T with zero-field Tc = 26.3 K, suggesting an unconventional nature for superconductivity.

12 pages and 4 figures

References in corpus (8)

• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Very High Field Two-Band Superconductivity in LaFeAsO_0.89F_0.11
• Superconductivity at 52 K in iron-based F-doped layered quaternary compound Pr[O1-xFx]FeAs
• The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
• Electron Correlations in the Low Carrier Density LaFeAsO0.89F0.11 Superconductor (Tc = 28 K)
• A possible ground state and its electronic structure of a mother material (LaOFeAs) of new superconductors
• Superconducting Gap and Pseudogap in Iron-Based Layered Superconductor La(O${}_{1-x}$F${}_x$)FeAs

Cited by in corpus (2)

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• Point-contact Andreev-reflection spectroscopy in ReFeAsO_{1-x}F_x (Re = La, Sm): Possible evidence for two nodeless gaps