Thermally activated energy and critical magnetic fields of SmFeAsO_(0.9)F_(0.1)

Thermally activated flux flow and vortex glass transition of recently discovered SmFeAsO$_{0.9}$F$_{0.1}$ superconductor are studied in magnetic fields up to 9.0 T. The thermally activated energy is analyzed in two analytic methods, of which one is conventional and generally used, while the other is closer to the theoretical description. The thermally activated energy values determined from both methods are discussed and compared. In addition, several critical magnetic fields determined from resistivity measurements are presented and discussed.