Upper and lower critical fields in NdFeAs(O,F) single crystals : a study by Hall probe magnetization and specific heat

Abstract

The upper and lower critical fields have been deduced from specific heat and Hall probe magnetization measurements in non-optimally doped NdFeAs(O,F) single crystals ($T_c\sim 32-35$K). The anisoptropy of the penetration depth (${\Gamma }_{\lambda }$) is temperature independent and on the order of $4.0\pm 1.5$. Similarly specific heat data lead an anisotropy of the coherence lenght ${\Gamma }_{\xi }\sim 5.5\pm 1.5$ close to $T_c$. Our results suggest the presence of rather large thermal fluctuations and to the existence of a vortex liquid phase over a broad temperature range ($\sim 5$K large at 2T).

References in corpus (19)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• LaFeAsO${}_{1-x}$F${}_x$: A low carrier density superconductor near itinerant magnetism
• Superconductivity in iron-based F-doped layered quaternary compound Nd[O1-xFx]FeAs
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Anisotropy of the Upper Critical Field and Critical Current in Single Crystal MgB${}_2$
• Field and Temperature Dependence of the Superfluid Density in LaO_{1-x}F_xFeAs Superconductors: A Muon Spin Relaxation Study
• Critical Fields and Anisotropy of NdO0.82F0.18FeAs Single Crystals
• Upper critical field, anisotropy, and superconducting properties of Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ single crystals
• Upper critical fields well above 100 T for the superconductor SmFeAsO${}_{0.85}$F${}_{0.15}$ with T${}_c$ = 46 K
• Coexistence of magnetic fluctuations and superconductivity in the pnictide high temperature superconductor SmFeAsO${}_{1-x}$F${}_x$ measured by muon spin rotation
• Muon-spin rotation studies of SmFeAsO_0.85 and NdFeAsO_0.85 superconductors
• Anisotropies of the lower and upper critical fields in MgB${}_2$ single crystals
• Spin Ordering in LaOFeAs and Its Suppression in Superconductor LaO0.89F0.11FeAs Probed by Mössbauer Spectroscopy
• Caloric Determination of the Upper Critical Fields and Anisotropy of NdFeAsO1-xFx Single Crystals
• Superconducting energy gap and c-axis plasma frequency of (Nd,Sm)O0.82F0.18FeAs superconductors from infrared ellipsometry
• Angular dependence of resistivity in the superconducting state of NdFeAsO${}_{0.82}$F${}_{0.18}$ single crystals
• Anomalous magnetic field dependence of the thermodynamic transition line in the isotropic superconductor (K,Ba)Bi03

Cited by in corpus (25)

• Pauli-limited upper critical field in Fe1+yTe1-xSex
• Flux pinning in (1111) iron-pnictide superconducting crystals
• Two-gap and paramagnetic pair-breaking effects on upper critical field of SmFeAsO${}_{0.85}$ and SmFeAsO${}_{0.8}$F${}_{0.2}$ single crystals
• Thermodynamic phase diagram of Fe(Se${}_{0.5}$Te${}_{0.5}$) single crystals up to 28 Tesla
• High-pressure flux growth, structural, and superconducting properties of LnFeAsO (Ln = Pr, Nd, Sm) single crystals
• Charge doping-induced quasiparticle scattering in iron-pnictide superconductors as probed by vortex pinning
• Lower Critical Fields of Superconducting PrFeAsO${}_{1-y}$ Single Crystals
• Th substituted SmFeAsO: structural details and superconductivity with Tc above 50 K
• Anisotropic superconductivity and magnetism in single-crystal RbEuFe${}_4$As${}_4$
• Anisotropic Phase Diagram and Superconducting Fluctuations in SmFeAsO0.85F0.15
• Measurements of the lower critical field of superconductors using NV centers in diamond optical magnetometry
• Effects of excess Fe on upper critical field and magnetotransport in Fe1+y(Te1-xSx)z
• Anisotropy of strong pinning in multi-band superconductors
• Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap
• Anisotropic fluctuations and quasiparticle excitations in FeSe_0.5Te_0.5
• Thermodynamics of transition to BCS-BEC crossover superconductivity in FeSe${}_{1-x}$S${}_x$
• Effect of columnar defects on the pinning properties of NdFeAsO0.85 conglomerate particles
• Magnetic and transport properties of iron-platinum arsenide Ca10(Pt4-δAs8)(Fe2-xPtxAs2)5 single crystal
• Single Vortex Pinning and Penetration Depth in Superconducting NdFeAsO${}_{1-x}$F${}_x$
• Self-consistent two-gap approach in studying multi-band superconductivity in NdFeAsO${}_{0.65}$F${}_{0.35}$
• Fluctuation magnetoconductivity in pristine and protonirradiated Ca8.5La1.5(Pt3As8)(Fe2As2)5 single crystals
• Scaling of the physical properties in Ba(Fe,Ni)2As2 single crystals: Evidence for quantum fluctuations
• Anisotropies and Homogeneities of Superconducting Properties in Iron-Platinum-Arsenide Ca10(Pt3As8)(Fe1.79Pt0.21As2)5
• Determination of the magnetic penetration depth with measurements of the vortex-penetration field for type-II superconductors
• Lower Critical Field Hc1(T) and Pairing Symmetry Based on Eilenberger Theory