23 research outputs found
Normal state resistivity of BaKFeAs: evidence for multiband strong-coupling behavior
We present theoretical analysis of the normal state resistivity in multiband
superconductors in the framework of Eliashberg theory. The results are compared
with measurements of the temperature dependence of normal state resistivity of
high-purity BaKFeAs single crystals with the
highest reported transition temperature = 38.5 K. The experimental data
demonstrate strong deviations from the Bloch-Gr\"{u}neisen behavior, namely the
tendency to saturation of the resistivity at high temperatures. The observed
behavior of the resistivity is explained within the two band scenario when the
first band is strongly coupled and relatively clean, while the second band is
weakly coupled and is characterized by much stronger impurity scattering.Comment: 4 pages, 3 figures, to be published in JETP Letters Vol.94, N
Transport properties and the anisotropy of Ba_{1-x}K_xFe_2As_2 single crystals in normal and superconducting states
The transport and superconducting properties of Ba_{1-x}K_xFe_2As_2 single
crystals with T_c = 31 K were studied. Both in-plane and out-of plane
resistivity was measured by modified Montgomery method. The in-plane
resistivity for all studied samples, obtained in the course of the same
synthesis, is almost the same, unlike to the out-of plane resistivity, which
differ considerably. We have found that the resistivity anisotropy
\gamma=\rho_c /\rho_{ab} is almost temperature independent and lies in the
range 10-30 for different samples. This, probably, indicates on the extrinsic
nature of high out-of-plane resistivity, which may appear due to the presence
of the flat defects along Fe-As layers in the samples. This statement is
supported by comparatively small effective mass anisotropy, obtained from the
upper critical field measurements, and from the observation of the so-called
"Friedel transition", which indicates on the existence of some disorder in the
samples in c-direction.Comment: 5 pages, 5 figure