Direct measurement of the temperature dependence of the magnetic penetration depth in Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$ superconductors

Abstract

The temperature dependence of the in-plane magnetic penetration depth ${\lambda }_{ab}$ of Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$ single crystals is determined directly from the shielding magnetic susceptibility, measured in the Meissner region with the field parallel to the ab layers. The doping levels studied cover the underdoped, optimally-doped and overdoped regimes. At temperatures below 0.5Tc a well-defined power-law behavior ${\lambda }_{ab}(T)-{\lambda }_{ab}(0)=A{T}^n$ (with n approximately 2.5) is observed. At lower temperatures (T<0.3Tc) the data are still consistent with n=2 and $A\propto T_c^{-3}$, as predicted by the strong pair-breaking scenario proposed by Gordon et al., Phys. Rev. B 81, 180501(R) (2010). The temperature dependence of the superfluid density ${\rho }_s\propto {\lambda }_{ab}^{-2}$ presents a marked positive curvature just below Tc which is a sign of two-gap superconductivity. The analysis of ${\rho }_s(T)$ in terms of a two-gap model allowed to estimate parameters like the in-band and inter-band couplings, the relative weight of each band, and their dependence with the doping level. A comparison with ${\rho }_s(T)$ data obtained by using other techniques in compounds with a similar composition is also presented.

arXiv comment18 pages, including 6 figures and 2 tables

References in corpus (46)

• Superconductivity in Iron Compounds
• Microwave Penetration Depth and Quasiparticle Conductivity in PrFeAsO_1-y Single Crystals : Evidence for a Full-Gap Superconductor
• Line nodes in the energy gap of high-temperature superconducting BaFe_2(As_{1-x}P_x)_2 from penetration depth and thermal conductivity measurements
• Evidence for nodal superconductivity in LaFePO
• London Penetration Depth in Iron - based Superconductors
• Evidence for superconducting gap nodes in the zone-centered hole bands of KFe2As2 from magnetic penetration-depth measurements
• Field and Temperature Dependence of the Superfluid Density in LaO_{1-x}F_xFeAs Superconductors: A Muon Spin Relaxation Study
• Anisotropy of the Optimally-Doped Iron Pnictide Superconductor Ba(Fe0.926Co0.074)2As2
• Microwave Surface-Impedance Measurements of the Magnetic Penetration Depth in Single Crystal Ba1-xKxFe2As2 Superconductors: Evidence for a Disorder-Dependent Superfluid Density
• Unconventional London penetration depth in Ba(Fe0.93Co0.07)2As2 single crystals
• Superfluid density and specific heat within self-consistent scheme for two-band superconductor
• Universal Decomposition of the Low-Frequency Conductivity Spectra of Iron-Pnictides Uncovering Fermi-Liquid Behavior
• Anisotropic superconducting properties of single-crystalline FeSe0.5Te0.5
• Evidence for Nodal Superconductivity in LaFePO from Scanning SQUID Susceptometry
• Superfluid density and penetration depth in Fe-pnictides
• Evolution of two-gap behavior of the superconductor FeSe_1-x
• Muon-spin rotation studies of SmFeAsO_0.85 and NdFeAsO_0.85 superconductors
• The London penetration depth in single crystals of Ba(Fe_{1-x}Co_x)_2As_2 at various doping levels
• Magnetic penetration depth of single crystal SmFeAsO_{1-x}F_y: a fully gapped superconducting state
• Nodeless vs nodal order parameters in LiFeAs and LiFeP superconductors
• Non-exponential London penetration depth in RFeAsO${}_{0.9}$F${}_{0.1}$ (R=La,Nd) single crystals
• Local measurement of the penetration depth in the pnictide superconductor Ba(Fe${}_{0.95}$Co${}_{0.05}$)${}_2$As${}_2$
• Thermodynamic phase diagram of Fe(Se${}_{0.5}$Te${}_{0.5}$) single crystals up to 28 Tesla
• Doping evolution of the absolute value of the London penetration depth and superfluid density in single crystals of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Local measurement of the superfluid density in the pnictide superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ across the superconducting dome
• Non-exponential London penetration depth in Ba${}_{1-}$K${}_x$Fe${}_2$As${}_2$ single crystals
• Muon Spin Rotation Measurement of the Magnetic Field Penetration Depth in Ba(Fe0.93 Co0.07)2 As2 : Evidence for Multiple Superconducting Gaps
• London penetration depth and superfluid density in single crystals of Fe(Te,Se) and Fe(Te,S) superconductors
• London penetration depth in Ba(Fe${}_{1-x}$T${}_x$)${}_2$As${}_2$ (T=Co, Ni) superconductors irradiated with heavy ions
• London penetration depth and strong pair-breaking in iron-based superconductors
• Anisotropic London Penetration Depth and Superfluid Density in Single Crystals of Iron-based Pnictide Superconductors
• Three-dimensional nodal superconducting gap in single crystals Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$
• Highly anisotropic energy gap in superconducting Ba(Fe${}_{0.9}$Co${}_{0.1}$)${}_2$As${}_2$ from optical conductivity measurements
• Doping - dependent superconducting gap anisotropy in the two-dimensional 10-3-8 pnictide Ca${}_{10}$(Pt${}_3$As${}_8$)[(Fe${}_{1-x}$Pt${}_x$)${}_2$As${}_2$]${}_5$
• Magnetic and superconducting transitions in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ studied by specific heat
• Observation of a coherence peak and pair-breaking effects in THz conductivity of BaFe${}_{2-2x}$Co${}_{2x}$As${}_2$
• Superfluid density measurements of Ba(CoxFe1-x)2As2 films near optimal doping
• Precision Microwave Electrodynamic Measurements of K- and Co-doped BaFe${}_2$As${}_2$
• Microscopic Study of the Superconducting State of the Iron Pnictide RbFe_2As_2
• How robust the global measurements of London penetration depth are: the case of Fe(Te${}_{1-x}$,Se${}_x$)
• Doping - dependent anisotropic superconducting gap in Na${}_{1-\delta }$(Fe${}_{1-x}$Co${}_x$)As
• Evidence for line nodes in the energy gap of the overdoped Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ from low-temperature specific heat measurements
• Nodal superconductivity in isovalently substituted SrFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ pnictide superconductor at the optimal doping, $x=$0.35
• Agreement between local and global measurements of the London penetration depth
• Scaling of the physical properties in Ba(Fe,Ni)2As2 single crystals: Evidence for quantum fluctuations
• Reply to "Comment on \emph{"Precision global measurements of London penetration depth in Fe(Te${}_{0.58}$Se${}_{0.42}$)"}"

Cited by in corpus (3)

• Nodeless superconductivity in the presence of spin-density wave in pnictide superconductors: The case of BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Superconducting fluctuations in isovalently-substituted BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$: Possible observation of multiband effects
• Enhancement of the critical current by surface irregularities in Fe-based superconductors