Magnetic scattering and electron pair breaking by rare-earth-ion substitution in BaFe2As2 epitaxial films

Abstract

The effect of electron doping by trivalent charge state rare-earth ion (RE = La, Ce, Pr, and Nd) substitutions on the superconductivity in BaFe2As2 was examined using epitaxial films. Each of the RE substitutions suppressed the resistivity anomaly associated with the magnetic/structural phase transitions, leading to the resistivity drops and superconductivity transitions. Bulk superconductivity was observed at the maximum onset critical temperature (Tconset) of 22.4 K for La-doping and 13.4 K for Ce-doping, while only broad resistivity drops were observed at 6.2 K for Pr-doping and 5.8 K for Nd-doping but neither zero resistivity nor distinct Meissner effect were observed at least down to 2 K. The decrease in Tconset with increasing the number of RE 4f electrons cannot be explained in terms of the crystalline qualities or crystallographic structure parameters of the BaFe2As2 films. It was clarified, based on resistivity-temperature analyses, that magnetic scattering became increasingly significant in the above order of the RE dopants. The negative magnetoresistance was enhanced by the Ce- and Pr-doping, implying that the decrease in Tc originates from magnetic pair breaking by interaction of the localized 4f orbitals in the RE dopants with the itinerant Fe 3d orbitals.

To be published in New Journal of Physics

References in corpus (17)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 22 K in Co-doped BaFe2As2 Crystals
• Evidence for an electron nematic phase transition in underdoped iron pnictide superconductors
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• Effects of Co substitution on thermodynamic and transport properties and anisotropic $H_{c2}$ in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ single crystals
• Superconductivity in SrFe_(2-x)Co_xAs_2: Internal Doping of the Iron Arsenide Layers
• AFe2As2 (A = Ca, Sr, Ba, Eu) and SrFe_(2-x)TM_(x)As2 (TM = Mn, Co, Ni): crystal structure, charge doping, magnetism and superconductivity
• Electron and hole Dirac cone states in-pairs in Ba(FeAs)${}_2$ confirmed by magnetoresistance
• The Unusual Superconducting State at 49 K in Electron-Doped CaFe2As2 at Ambient
• High Critical Current Density 4 MA/cm2 in Co-Doped BaFe2As2 Epitaxial Films Grown on (La, Sr)(Al, Ta)O3 Substrates without Buffer Layers
• Control of tetrahedral coordination and superconductivity in FeSe0.5Te0.5 thin films
• Thin Film Growth and Device Fabrication of Iron-Based Superconductors
• Synthesis and properties of La-doped CaFe2As2 single crystals with Tc = 42.7 K
• Thin film growth by pulsed laser deposition and properties of 122-type iron-based superconductor AE(Fe1--xCox)2As2 (AE = alkaline earth)
• Identical effects of indirect and direct electron doping of superconducting BaFe2As2 thin films
• Upper critical field anisotropy in BaFe2-xCoxAs2 single crystals synthesized without flux
• Unusual pressure effects on the superconductivity of indirectly electron-doped (Ba1-xLax)Fe2As2 epitaxial films

Cited by in corpus (6)

• Exploration of new superconductors and functional materials and fabrication of superconducting tapes and wires of iron pnictides
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• Superconductivity in La1-xCexOBiSSe: carrier doping by mixed valence of Ce ions
• High-Pressure Evolution of the Specific Heat of a Strongly Underdoped Ba(Fe0.963Co0.037)As2 Iron-Based Superconductor
• Novel method to study strain effect of thin films using a piezoelectric-based device and a flexible metallic substrate