Results of X-band microwave surface impedance measurements of FeSe1-xTex very
thin film are reported. The effective surface resistance shows appearance of
peak at T less and near Tc when plotted as function of temperature. The authors
suggests that the most well-reasoned explanation can be based on the idea of
the changing orientation of the microwave magnetic field at a SN phase
transition near the surface of a very thin film. The magnetic penetration depth
exhibits a power-law behavior of delta lambda proportional to T with an
exponent n = 2.4 at low temperatures, which is noticeably higher than in the
published results on FeSe1-xTexsingle crystal. However the temperature
dependence of the superfluid conductivity remains very different from the
behavior described by the BCS theory. Experimental results are fitted very well
by a two-gap model with delta1/kTc=0.43 and delta2/kTc=1.22,thus supporting
s(+-)- wave symmetry. The rapid increase of the quasiparticle scattering time
is obtained from the microwave impedance measurements.Comment: 13 pages, 13 figure
