Superfluid Density and Field-Induced Magnetism in Ba(Fe1-xCox)2As2 and Sr(Fe1-xCox)2As2 Measured with Muon Spin Relaxation

Abstract

We report muon spin rotation ($\mu$SR) measurements of single crystal Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ and Sr(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$. From measurements of the magnetic field penetration depth $\lambda$ we find that for optimally- and over-doped samples, $1/\lambda (T\to 0{)}^2$ varies monotonically with the superconducting transition temperature T${}_{\mathrm{C}}$. Within the superconducting state we observe a positive shift in the muon precession signal, likely indicating that the applied field induces an internal magnetic field. The size of the induced field decreases with increasing doping but is present for all Co concentrations studied.

7 pages, accepted for publication in Phys. Rev. B

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Cited by in corpus (6)

• Local measurement of the superfluid density in the pnictide superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ across the superconducting dome
• Effect of annealing on the specific heat of Ba(Fe1-xCox)2As2
• Muon spin rotation study of magnetism and superconductivity in Ba(Fe1-xCox)2As2 single crystals
• ${}^{75}$As NMR of Ba(Fe${}_{0.93}$Co${}_{0.07}$)${}_2$As${}_2$ in High Magnetic Field
• Muon spin rotation and infrared spectroscopy study of magnetism and superconductivity in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• Scaling of the physical properties in Ba(Fe,Ni)2As2 single crystals: Evidence for quantum fluctuations