Effect of heavy-ion irradiation on London penetration depth in overdoped Ba(Fe1−xCox)2As2

J. Murphy, M. A. Tanatar, Hyunsoo Kim, W. Kwok, U. Welp, D. Graf, J. S. Brooks, S. L. Bud'ko, P. C. Canfield, R. Prozorov
2013 Physical Review B  
Irradiation with 1.4 GeV ^208Pb ions was used to induce artificial disorder in single crystals of iron-arsenide superconductor Ba(Fe_1-xCo_x)_2As_2 and to study its effect on the temperature-dependent London penetration depth and transport properties. Study was undertaken on overdoped single crystals with x=0.108 and x=0.127 characterized by notable modulation of the superconducting gap. Irradiation with doses 2.22×10^11d/cm^2 and 2.4×10^11d/cm^2, corresponding to the matching fields of B_ϕ = 6
more » ... T and 6.5 T, respectively, suppresses the superconducting T_c by approximately 0.3 to 1 K. The variation of the low-temperature penetration depth in both pristine and irradiated samples is well described by the power-law, Δλ (T)=AT^n. Irradiation increases the magnitude of the pre-factor A and decreases the exponent n, similar to the effect of irradiation in optimally doped samples. This finding supports universal s_± pairing in Ba(Fe_1-xCo_x)_2As_2 compounds for the whole Co doping range.
doi:10.1103/physrevb.88.054514 fatcat:odbz6lvb6vdxrgz6rc5aigrpsu