Upper critical field, penetration depth, and depinning frequency of the novel high-temperature superconductor LaFeAsO$_{0.9}$F$_{0.1}$ studied by microwave surface impedance

Temperature and magnetic field dependent measurements of the microwave surface impedance of superconducting LaFeAsO$_{0.9}$F$_{0.1}$ (Tc $approx$ 26K) reveal a very large upper critical field ($B_{rm c2} approx 56$T) and a large value of the depinning frequency ($f_{0}approx 6$GHz); together with an upper limit for the effective London penetration depth, $lambda_{rm eff} le 200 rm nm$, our results indicate a strong similarity between this system and the high-$T_{rm c}$ superconducting cuprates.